- Email: [email protected]
Cardiac catheterization techniques in pulmonary hypertension
Cardiol Clin 22 (2004) 401–415
Cardiac catheterization techniques in pulmonary hypertension Paulo Guillinta, MD, Kirk L. Peterson, MD, Ori Ben-Yehuda, MD* Division of Cardiology, Department of Medicine, University of California, San Diego, 200 West Arbor Drive, San Diego, CA 92110, USA
Once considered dangerous and potentially life threatening, cardiac catheterization of the patient with pulmonary hypertension can be performed safely and provides essential information in the diagnosis and management of pulmonary hypertension. This article summarizes the modern techniques used for right-heart catheterization, selective pulmonary angiography, and pulmonary angioscopy in the evaluation of the patient with pulmonary hypertension or with suspected chronic thromboembolic disease. Cardiac catheterization of the patient with suspected pulmonary hypertension is essential to determine accurately the cause and extent of disease. In patients with suspected chronic thromboembolic pulmonary hypertension (CTEPH), pulmonary angiography remains an essential part of the diagnostic evaluation and selection of appropriate patients for surgical pulmonary thrombendarterectomy. Although historically pulmonary angiography has been considered contraindicated in the presence of severe pulmonary hypertension, advances in cardiac and pulmonary angiographic techniques allow this procedure to be performed in a safe manner with acceptable risk. In reviewing the technique of right-heart catheterization, pulmonary angiography, and angioscopy in the patient with pulmonary hypertension, the authors draw on the experience of more than 20 years of catheterization of patients with severe pulmonary hypertension at the University of California, San Diego (UCSD) Medical Center,
* Corresponding author. E-mail address: [email protected] (O. Ben-Yehuda).
where more than 2500 such procedures have been performed.
Indications and considerations for catheterization of the patient with pulmonary hypertension Catheterization plays an integral part in the evaluation of the patient with pulmonary hypertension. The primary goals of catheterization are to determine right ventricular and pulmonary artery hemodynamics, to exclude left-to-right cardiac shunts and any significant left-sided cardiac disorder, to assist in the determination of the cause of pulmonary hypertension, and to test the response of therapeutic agents. In patients with suspected CTEPH, pulmonary angiography and angioscopy are used to assess clot location, extent, and size to determine candidacy for pulmonary thrombendarterectomy.
Safety considerations Early case reports [1–4] of fatalities associated with pulmonary angiography in patients with pulmonary hypertension have led to a lingering perception that the procedure is associated with considerable risk, primarily because of acute right ventricular failure and arrhythmias. Even rightheart catheterization alone [5] was reported to be potentially dangerous. Larger series have since been published, both in acute and chronic pulmonary embolism and in mild as well as severe pulmonary hypertension. Mills et al [6] described three deaths in 1350 patients (incidence of 0.2%), all of whom had right ventricular end diastolic pressure of 20 mm Hg or higher. Nicod et al [7]
0733-8651/04/$ - see front matter Ó 2004 Elsevier Inc. All rights reserved. doi:10.1016/j.ccl.2004.04.011
402
P. Guillinta et al / Cardiol Clin 22 (2004) 401–415
reported on the original series of 67 patients from UCSD undergoing CTEPH evaluation. Mean pulmonary arterial pressures (PAPs) were 47 13 mm Hg, with a right ventricular end diastolic pressure of 13 6 mm Hg and a cardiac index of 2.2 0.7 L/min. There were no deaths attributable to CTEPH. By 1991 this series had expanded to include more than 300 patients, without a death. Since then right-heart catheterization and pulmonary angiography have been performed in approximately 200 patients with severe pulmonary hypertension annually at UCSD, without a death related to the procedure (more than 2500 patients to date). There thus are no absolute contraindications to pulmonary angiography, and the procedure can be performed safely, provided certain precautions and advances in technique are employed. Nonfatal adverse reactions include transient hypotension and general catheterization-related adverse events such as inadvertent arterial puncture, oversedation, pneumothorax, and contrast agent–related nephropathy [8]. To minimize these risks, the authors use the following procedures at UCSD [9]: 1. Before the procedure echocardiography is performed, detecting potential clots in the right atrium or right ventricle or the presence of an atrial septal defect/patent foramen ovale. 2. Heart rate, rhythm, oxygen saturation, and systemic and PAP should be continuously monitored. Supplemental oxygen is provided to maintain oxygen saturation over 90%. 3. Access to the pulmonary vessels through the neck is preferred to avoid potential dislodgement of unsuspected venous thrombi involving the femoral vein, iliac vein, or inferior vena cava and to facilitate angioscopy. The authors prefer the internal jugular vein to the subclavian vein to reduce the risk of pneumothorax, which is likely to be poorly tolerated in these patients who are often hypoxemic. 4. Hemodynamics are assessed using a balloon flotation catheter (Swan-Ganz catheter), at times stiffened with a 0.025-cm guide wire. This stiffening greatly facilitates the catheterization in these patients, who frequently have enlarged right ventricles, significant tricuspid regurgitation, severely elevated PAPs, and low cardiac output. CO2 is used for balloon inflation to minimize the possi-
5.
6.
7.
8.
bility of paradoxical embolism in case of balloon rupture. A stiff, side-hole catheter such as a 7-F or 8-F NIH or Berman catheter is most commonly used to inject the pulmonary arteries. The injection through the side holes allows good opacification with reduced injection velocity and pressure. Catheter retraction and whipping during injection are also minimized. Unilateral, sequential injection of the contrast agent in to each main pulmonary artery is preferred. Injection into the right atrium or right ventricle is avoided, thereby eliminating the possibility of intramyocardial injection. The catheter is positioned near the origin of the lower lobe vessels, and the contrast agent is allowed to fill the upper lobes in retrograde fashion. Non-ionic contrast is preferred because fewer adverse reactions and minimal hemodynamic compromise are experienced [10,11]. Cardiac output and speed of run-off during small hand injection are used to determine the amount of contrast agent needed for assessment of the pulmonary vasculature anatomy. A smaller amount of contrast material is needed in patients with slow run-off or low cardiac output. At UCSD, the total amount of contrast medium used ranges from 20 to 65 mL. The usual injection is of 55 mL at a rate of 22 mL/second, with adjustments based on the patient’s cardiac output, assessment of the pulmonary vasculature during the hand injection, and pulmonary pressures. For example, the total occlusion of the main descending pulmonary artery after the takeoff of the upper lobe branch would necessitate a reduction of the total contrast to approximately 20 mL. Conversely, the presence of a brisk runoff during the hand injection coupled with a high cardiac output would lead to injection of more than the standard 55 mL.
Right-heart catheterization Evaluation of hemodynamics by right-heart catheterization plays an integral part of the evaluation of patients with pulmonary hypertension. The goals of right-sided catheterization are (1) to measure PAP directly and estimate pulmonary vascular resistance, (2) to evaluate for left-toright shunts, and (3) to test the response to therapeutic agents.
P. Guillinta et al / Cardiol Clin 22 (2004) 401–415
During right-heart catheterization by balloon flotation catheter, rapid determination and continuous monitoring of pressures in the right ventricle, right atrium, and pulmonary artery and of postcapillary wedge pressure are possible. Understanding of normal and pathologic pressure waveforms is important to recognize certain cardiac disorders such as valvular and pericardial disease. In patients with primary pulmonary hypertension (PPH), particular attention should be paid to the right atrial pressure and right ventricle end-diastolic pressure. In the National Heart Lung and Blood Institute registry, mean right atrial pressure and decreased cardiac index were the most important predictive variables for survival in patients with PPH [12]. The patient with PPH commonly has elevated right atrial pressure, elevated mean PAP, reduced cardiac index, and low or normal postcapillary wedge pressure [8]. A postcapillary wedge pressure is obtained with an end-hole catheter positioned in a side branch of the pulmonary artery facing a pulmonary capillary bed. One pitfall to avoid is wedging the balloon too proximally, creating a hybrid tracing of pressures between actual PAP and postcapillary wedge pressure, resulting in an overestimation of the postcapillary wedge pressure (Fig. 1). Deflating the balloon to decrease its size will allow the catheter to be wedged in a smaller, more distal branch of the pulmonary artery. Caution should be taken to avoid overwedging and possible pulmonary artery rupture, a potentially lethal event. Fortunately in pulmonary hypertension the thickened, hypertrophied arterial wall provides some protection against rupture. When it is not clear whether a wedge tracing has been obtained, a blood sample is obtained through the distal port. In the wedge position arterial saturation should be present as blood from the capillary bed is aspirated. The authors have also found that typically the more narrow, tapering anatomy of the left pulmonary artery allows more reliable wedge determinations. The use of a J-tipped 0.25 wire to guide the Swan-Ganz catheter to the left pulmonary artery is essential. Typically patients with either PPH or CTEPH have low to normal wedge pressures. In the presence of substantially elevated postcapillary wedge pressure, left-heart catheterization should be performed to exclude pulmonary venoocclusive disease, mitral stenosis, or left ventricular dysfunction. Cardiac output is best determined by the Fick method in the setting of low cardiac output states or when there is significant tricuspid regurgita-
403
tion. This method requires measuring oxygen consumption directly, because estimations of oxygen consumption may not apply to seriously ill patients with pulmonary hypertension and may introduce significant calculation errors. In experienced hands, however, determination of cardiac output by thermodilution techniques is usually satisfactory for the adjustment of therapy in these patients [13].
Response of vasodilator challenge in the cardiac catheterization laboratory Vasoconstriction of the pulmonary vessels is one of the prominent pathologic features seen in patients with pulmonary hypertension of any cause, particularly in those with PPH [14]. Unfortunately, no hemodynamic or demographic characteristics exist to predict which patients are likely to benefit from long-term vasodilator therapy [15,16]. In more recent studies, Groves et al [17] illustrated that the initial response to vasodilatory therapy accurately predicts the patient with PPH who is likely to benefit from long-term oral therapy. In addition, patients who demonstrate a reduction in total pulmonary resistance index of more than 50% in response to short-term epoprostenol (prostacyclin, PGI2) challenge at the time of diagnosis had longer disease evolutions and better prognoses than patients with a lower vasodilator response [18,19]. For these reasons [3], it is important to assess the response to vasodilator therapy in patients with PPH in the cardiac catheterization laboratory. Nitric oxide and PGI2 are useful drugs to test pulmonary vasoreactivity because they are potent, short acting, and can be titrated. The acute effects of inhaled nitric oxide and PGI2 on pulmonary artery pressure are similar [20,21]. Inhaled nitric oxide more consistently reflects the changes in pulmonary vascular tone and seems to be the better predictor of the long-term response to oral vasodilator treatment, making it the preferred agent for assessing pulmonary vasoreactivity [22]. Nitroprusside has fallen out of favor for assessing pulmonary vasoreactivity in patients with chronic pulmonary hypertension because this drug causes systemic hypotension compared with nitric oxide, at doses that cause similar degrees of pulmonary vasodilation [23]. Pulmonary arterial pressures, right ventricular pressures, cardiac output, and postcapillary wedge pressure are recorded during infusions of inhaled
404
P. Guillinta et al / Cardiol Clin 22 (2004) 401–415
Fig. 1. (A) Hybrid tracing of pulmonary artery pressure and wedge tracing overestimating wedge pressure. (B) Actual pulmonary capillary wedge pressure tracing once the balloon is deflated and allowed to wedge in a smaller, more distal branch of the pulmonary artery.
P. Guillinta et al / Cardiol Clin 22 (2004) 401–415
nitric oxide. Administration of inhaled nitric oxide with oxygen seems to be safe and provides additional pulmonary vasodilation in this patient population [24]. Pulmonary pressure are recorded during administration of 100% oxygen and inhaled nitric oxide dosed at 20 to 80 parts per million. The authors typically administer nitric oxide for 10 minutes, with repeat recordings obtained during the final 5 minutes of the inhalation. Although a mild reduction in pulmonary vascular resistance (<20%) can be seen in most patients, even those with CTEPH, significant reductions of more than 20% are seen in only one fourth of patients [25]. Pulmonary angiography: anatomy Accurate evaluation of the pulmonary angiogram requires knowledge of the pulmonary vas-
405
culature anatomy (Figs. 2 and 3). The main pulmonary artery arises from the pulmonary conus of the right ventricle, anterior and to the left of the aorta. It takes a posteromedial direction until its bifurcation into the right and left pulmonary arteries. The right pulmonary artery courses anterior to the right mainstem bronchus. It gives rise to the right upper lobe branch within the mediastinum. The left pulmonary artery passes over the left mainstem bronchus and descends posterior to the bronchus before the origin of the left upper lobe branch. The vessels then branch and are closely related to bronchial branching within the lung. Angiographic films are taken using anteroposterior and lateral projections. The lateral projection is particularly helpful in separating the overlapping tributaries of the right middle and right lower lobe and left lingual and left lower lobe. It also allows a clear separation
Fig. 2. (A) Anteroposterior view of the anatomy of the right pulmonary artery. (B) Lateral view. (Reproduced from Peterson KL, Nicod P. Catheterization and angiography in pulmonary hypertension. In: Shure D, Auger W, Moser K, et al, editors. Cardiac catheterization: methods, diagnosis, and therapy. Philadelphia: W.B. Saunders; 1977. p. 404; with permission.)
406
P. Guillinta et al / Cardiol Clin 22 (2004) 401–415
Fig. 3. Anatomy of the left pulmonary artery in (A) anteroposterior and (B) lateral views. (Reproduced from Peterson KL, Nicod P. Catheterization and angiography in pulmonary hypertension. In: Shure D, Auger W, Moser K, et al, editors. Cardiac catheterization: methods, diagnosis, and therapy. Philadelphia: W.B. Saunders; 1977. p. 405; with permission).
between the superior segmental artery and the artery to the middle lobe.
Pulmonary angiography: interpretation in the patient with pulmonary hypertension Pulmonary angiography of the patient with pulmonary hypertension plays a central role in delineating the precapillary cause of elevated pulmonary pressures. Distinguishing major-vessel from small-vessel disease allows the correct therapeutic approach to be determined. Auger et al [26] described the angiographic patterns seen in patients with chronic thromboembolic disease. These patterns include pouching abnormalities, vascular webs or bandlike constrictions, intimal irregularities, abrupt narrowing of
major pulmonary vessels, and obstruction of major pulmonary vessels, most commonly at points of origin (Figs. 4–8). Although pulmonary arterial webs are typically seen in patients with chronic thromboemboli, they are also seen in congenital stenotic lesions of the pulmonary vessels and with vasculitides such as Takayasu’s arteritis [27,28]. Patients with congenital stenotic lesions of the pulmonary vasculature present at an early age and typically have coexisting cardiac abnormalities. Most Takayasu patients with pulmonary vessel involvement demonstrate systemic manifestations. Total obstruction or abrupt narrowing of the pulmonary vessel, typically seen in chronic thromboemboli, can also be seen in extrinsic compression from extensive mediastinal or hilar lymphadenopathy, fibrosing mediastinitis, and pulmonary
P. Guillinta et al / Cardiol Clin 22 (2004) 401–415
407
Fig. 4. (A) The anteroposterior view of the right pulmonary artery in a patient with CTEPH. Note the marked hypovascularity, irregularity of the main descending pulmonary artery, and complete occlusion of most segmental branches. (B) The lateral view of the artery shown in 4A. Note the separation of the right middle lobe branches from the right lower lobe segments. In this view the middle lobe is perfused, as is the superior segment.
vascular or primary lung malignancies [29–32]. Chest CT aids in making the distinguishing these entities from chronic thromboembolic disease. Occasionally, several vascular abnormalities occur in the same patient. In this scenario, the pulmonary angiogram may aid in identifying the
Fig. 5. Right pulmonary angiogram shows central pulmonary artery enlargement and pouching abnormality in the right lower lobe vessel seen in chronic thromboembolic disease.
patient with acute on chronic thromboembolic disease (Fig. 9). Sharply defined luminal defects are seen in small, acute emboli. Proximal pulmonary artery enlargement and bandlike abnormalities are typically seen in chronic thromboembolic disease but not in acute embolic disease. The hemodynamic data can also assist in distinguishing chronic from acute embolism. Pulmonary hypertension with mean PAPs above 35 mm Hg suggest chronicity, because the right ventricle in acute pulmonary embolism without previous pulmonary hypertension is incapable of generating such high pulmonary pressures [33]. The classic angiographic findings in patients with PPH include normal or dilated central arteries with pruning of the small, more distal, nonelastic arteries [8]. Pruning of the pulmonary vessels may also be seen with chronic thromboembolic disease, but in this scenario pruning is regional and more proximal [34]. A key question that the pulmonary angiogram addresses in patients with suspected CTEPH is the extent and surgical accessibility of chronic clot. The presence of bilateral disease and proximal involvement (main pulmonary trunks, lobar arteries, and segmental arteries) predicts surgical accessibility. Correlation with findings on the perfusion scan is essential, because the presence
408
P. Guillinta et al / Cardiol Clin 22 (2004) 401–415
Fig. 6. (A) Anteroposterior view of the right pulmonary artery demonstrating hypoperfusion of the lower lobe. (B) Only on the lateral film does the extent of occlusion of the posterior basal segment and narrowing of the middle lobe branch become evident. The superior segment is also subtotally occluded.
of segmental defects is predictive of surgical success (see articles in this issue by Auger et al and Thistlethwaite et al).
When there is significant proximal disease (eg, complete occlusions of lobar vessels), the inter-
pretation of pulmonary angiograms is straightforward. In the UCSD experience the pulmonary angiogram is suggestive but not definitive in about 20% to 25% of cases. The recanalization of chronic clot allows contrast to permeate through the lesions, and the pulmonary angiogram can underestimate disease just as the perfusion scan can. In addition, the presence of defects at the
Fig. 7. Abrupt narrowing of the pulmonary vessel seen in chronic thromboembolic disease.
Fig. 8. Anteroposterior projection shows complete obstruction of the right main pulmonary artery.
Pulmonary angioscopy
P. Guillinta et al / Cardiol Clin 22 (2004) 401–415
Fig. 9. Anteroposterior view demonstrates acute on chronic thromboemboli. Note the distinct numerous luminal filling defects (solid arrow) in a bandlike or web abnormality.
transition between segmental and subsegmental vessels may raise doubt regarding the surgical accessibility. In the patient with markedly elevated pulmonary hypertension (pulmonary vascular resistance >800 dynes/second/cm5) surgical risks rise significantly if insignificant clot is removed during surgery, leaving the patient with severe pulmonary hypertension. Fiberoptic angioscopy, developed to allow direct visualization of the interior of the central pulmonary vessels up to the segmental and sub-
409
segmental levels, is used to define surgical accessibility better in borderline cases [35,36]. The challenges entailed in performing pulmonary angioscopy include the need to maneuver through an often hypertrophied right ventricle, the wide variation in pulmonary vessel size with varying anatomic branching, the large number of branches that require visualization, and the robust collateral circulation from the bronchial circulation. At UCSD pulmonary angioscopy has progressed through several stages of development over the past 20 years. The approach has been to use a balloon system to occlude blood flow completely in the vessel that is being visualized, rather than a flushing (hemodilution) approach as has been used in the coronary circulation. Hemodilution is not practicable in the large pulmonary arteries and would entail dangerous fluid overload in these patients with right-heart failure. The angioscope presently used is a 120-cm fiberoptic device, 3 mm in diameter (Figs. 10 and 11). It can be flexed 90( at the tip allowing navigation through the pulmonary tree. The occluding balloon is attached at a modified spool-like stainless steel lip, which allows secure tying of the disposable balloons. The balloon at the distal end is inflated with carbon dioxide to protect from air embolism in case of balloon rupture, a precaution of particular importance given the elevated rightsided pressures with potential for right- to-left embolism in patients with patent foramen ovale. The balloon is connected to a syringe by a tube in the angioscope, allowing deflation during the advancement of the catheter and inflation to occlude the vessel as well as allow flotation further downstream.
Fig. 10. The pulmonary angioscope. (Courtesy of Olympus Corporation, Lake Success, NY.)
410
P. Guillinta et al / Cardiol Clin 22 (2004) 401–415
Fig. 11. Inflated balloon attached to the distal tip of the angioscope.
Because of the size of the angioscope (3 mm) an 11-F sheath is used. Although angioscopy can be accomplished from the femoral approach, it is much easier to navigate the instrument through the right ventricle using the internal jugular vein approach, particularly from the right. Two operators are needed to guide the angioscope, with one advancing and torquing the instrument and the other flexing and extending it using the built-in deflectors. Angioscopy is most helpful in defining the starting point of chronic thrombi and establishing whether they are within surgical reach. This procedure enables the examiner to determine operability of patients with chronic pulmonary thromboemboli in approximately 75% of the cases when the findings on the pulmonary angiogram are questionable [34]. A detailed map of the major pulmonary vessels can be performed safely within 20 minutes, without significant morbidity, in this patient population. The main complications encountered have been transient ventricular ectopy during transit in the ventricle and minor local bleeding from the 11-F sheath site in the neck. During the procedure the fluoroscopy images are recorded to localize the lesions seen on angioscopy and are correlated with the anatomy as defined in the pulmonary angiogram. Normal pulmonary findings are of smooth, pale white, glistening intima (Fig. 12). Bifurcations are typically round and regular in appearance. In patients with pulmonary hypertension, either primary arterial hypertension or secondary to CTEPH, the arterial walls may demonstrate small, yellowish atheroscleroticlike plaques as well as more diffuse yellowish colorations (Figs. 13 and 14). Patients with chronic thrombi have irregular pulmonary arterial walls with transluminal bands
Fig. 12. Normal bifurcation of a pulmonary artery.
and obstructive lesions and irregular vessel ostia. Thin membranes can also be visualized. At times reddish-purplish subacute thrombi can be seen, which are distinct from the white fibrotic lesions of chronic organized and recanalized clot. Small-vessel arteriopathy in patients with chronic thromboembolic pulmonary hypertension Although the main site of vasculopathy and increased resistance in CTEPH is in the large, elastic pulmonary arteries, a significant number of patients have concomitant small-vessel arteriopathy that may persist despite the removal of proximal clot. These patients are at increased risk of persistent pulmonary hypertension after pulmonary thrombendarterectomy. Severe persistent pulmonary hypertension after surgery accounts for more than one third of perioperative mortality and up to 50% of long-term deaths. Recently the pulmonary artery occlusion technique [37] has been used to attempt to partition the pulmonary resistance into an upstream component (Rup) and downstream (small arterial plus venous) component. Using a standard Swan-Ganz catheter (Edwards Lifesciences Corporation, Irvine, CA) the pulmonary pressure signal is filtered using a twopole digital low-pass filter with a cutoff at 18 Hz. A biexponential fitting of the pressure decay curve is then performed, which allows estimation of the derived occlusion pressure (Poccl). Rup is then calculated as follows: Rup mean pulmonary artery pressure Poccl ¼ ð%Þ mean pulmonary artery pressure Ppao where Ppao is the final pulmonary artery occluded pressure (wedge pressure). In patients with
P. Guillinta et al / Cardiol Clin 22 (2004) 401–415
411
Fig. 13. Angioscopic findings in CTEPH. Note the fibrotic white material with membranes, webs, and pitting.
Fig. 14. Angioscopic findings in CTEPH. Note the yellow plaque prominent in B, G, and K. Membranes, webs, and masslike fibrotic tissue can be seen.
412
P. Guillinta et al / Cardiol Clin 22 (2004) 401–415
Fig. 15. Pulmonary artery pressure occlusion waveforms from two patients with (A) mainly upstream resistance and (B) mainly downstream resistance. In A the pressure drops more rapidly with balloon occlusion, resulting in lower Poccl and higher Rup%.
small-vessel arteriopathy the Poccl pressure is higher (a longer time is required for the pressure to reach Ppao), and therefore the Rup % is lower (Fig. 15). In a study [37] of 26 patients with suspected CTEPH, there was an excellent correlation between Rup % before pulmonary thrombendarterectomy and hemodynamic response to surgery. Moreover, all four patients with Rup % below 60 did not survive surgery (Fig. 16). Coronary arteriography Before pulmonary thrombendarterectomy the authors routinely perform coronary arteriography on all male patients above the age of 40 and female patients above the age of 45 and do so for
younger patients if findings are suggestive of coronary disease. In the presence of markedly enlarged proximal pulmonary arteries, the left main pulmonary artery may become compressed and give the appearance of ostial left main stenosis [38]. Best visualized in the let anterior oblique cranial view (Fig. 17), this finding is usually devoid of other evidence of atherosclerosis and is not in itself an indication for bypass surgery, especially if the patient’s pulmonary pressures decrease after surgery. Summary Cardiac catheterization of the patient with pulmonary hypertension plays an integral part in
P. Guillinta et al / Cardiol Clin 22 (2004) 401–415
413
Fig. 16. Correlation between preoperative Rup % and postoperative outcomes. (A) Postoperative pulmonary resistance (B) Mean postoperative pulmonary pressure. (Reproduced from Kim NH, Fesler P, Channick RN, et al. Preoperative pulmonary partitioning of pulmonary vascular resistance correlates with early outcome after thromboendarterectomy for chronic thromboembolic pulmonary hypertension circulation. 2004;109:19; with permission.)
414
P. Guillinta et al / Cardiol Clin 22 (2004) 401–415
Fig. 17. Left main ostial compression from an enlarged pulmonary artery. (Reproduced from Bonderman D, Fleischmann D, Prokop M, et al. Imges in cardiovascular medicine. Left main coronary artery compression by the pulmonary trunk in pulmonary hypertension. Circulation 2002;105:265; with permission.)
the diagnostic evaluation. Right-heart hemodynamics, pulmonary angiography, and pulmonary angioscopy offer a way to determine the cause of disease safely and accurately and to offer potentially life-saving therapies.
References [1] Dotter CT, Jackson FS. Death following angiocardiography. Radiology 1950;54:527–33. [2] Diamond EG, Gonlubol F. Death following angiocardiography: report of two cases after administration of diodrast and neo-iopax, respectively. N Engl J Med 1953;249:1029–31. [3] Alexander JK, Gonzales DA, Fred HL. Angiographic studies in cardiorespiratory diseases: special reference to thromboembolism. JAMA 1966;198: 575–8. [4] Snider GL, Ferris E, Gaensler EA, et al. Primary pulmonary hypertension: a fatality during pulmonary angiography. Chest 1973;64:628–35. [5] Caldini P, Gensini GG, Hoffman MS. Primary pulmonary hypertension with death during right heart catheterization. Am J Cardiol 1959;519–27. [6] Mills SR, Jackson DC, Older RA, et al. The incidence, etiologies, and avoidance of complications of pulmonary angiography in a large series. Radiology 1980;136:295–9. [7] Nicod P, Peterson KL, Levine M, et al. Pulmonary angiography in severe chronic pulmonary hypertension. Ann Intern Med 1987;107:565–8. [8] Rich S, Dantzker DR, Ayres SM, et al. Primary pulmonary hypertension: a national prospective study. Ann Intern Med 1987;107:216–23.
[9] Peterson KL, Nicod P. Catheterization and angiography in pulmonary hypertension. In: Shure D, Auger W, Moser K, et al, editors. Cardiac catheterization: methods, diagnosis, and therapy. Philadelphia: W.B. Saunders; 1977. p. 401–14. [10] Kumazaki T. Ioxaglate versus diatrizoate in selective pulmonary angiography. Part II: cardiovascular responses. Acta Radiol 1985;26:635. [11] Smith DC, Lois JF, Gomes AS, et al. Pulmonary angiography: comparison of cough stimulation effects of diatrizoate and ioxaglate. Radiology 1987; 162:617–8. [12] D’Alonzo GE, Barst RJ, Ayres SM, et al. Survival in patients with primary pulmonary hypertension: result from a national prospective registry. Ann Intern Med 1991;115:343–9. [13] Rubin LW, Rich S. Primary pulmonary hypertension. In: Georgiou D, Cao T, Shapiro S, et al, editors. Hemodynamic evaluation in primary pulmonary hypertension. New York: Marcel Dekker; 1997. p. 253–86. [14] Wagenvoort CA. Vasoconstriction and medial hypertrophy in pulmonary hypertension. Circulation 1960;22:535–46. [15] Weir EK, Rubin LJ, Ayres SM, et al. The acute administration of vasodilator therapy in primary pulmonary hypertension: experience from the National Institute of Health Registry on Primary Pulmonary Hypertension. Am Rev Resp Dis 1989; 140:1623–40. [16] Weir EK. Acute vasodilator testing and pharmacological treatment of primary pulmonary hypertension. In: Fishman AP, editor. The pulmonary circulation: normal and abnormal: mechanisms, management and the national registry. Philadelphia: University of Pennsylvania Press; 1990. p. 485–99. [17] Groves BM, Badesch DB, Turkevich D, et al. Correlation of acute prostacyclin response in primary (unexplained) pulmonary hypertension with efficacy of treatment with calcium channel blockers and survival. In: Hummes JR, Reeves JT, Weir EK, editors. Ion flux in pulmonary vascular control. New York: Plenum Press; 1993. p. 317–30. [18] Rich S, Brundage BH. High-dose calcium channelblocking therapy for primary pulmonary hypertension: evidence of long-term reduction in pulmonary arterial hypertension and regression of right ventricular hypertrophy. Circulation 1987;76:135–41. [19] Olivier R, Re´za A, Franc¸ois B, et al. Clinical significance of the pulmonary vasodilator response during short-term infusion of prostacyclin in primary pulmonary hypertension. Circulation 1996; 93:484–8. [20] Rich S, Kaufmann E, Levy PS. The effects of high doses of calcium-channel blocker on survival in primary pulmonary hypertension. N Engl J Med 1992;327:76–81.
P. Guillinta et al / Cardiol Clin 22 (2004) 401–415 [21] Sitbon O, Brenot F, Denjean A, et al. Inhaled nitric oxide as a screening vasodilator agent in primary pulmonary hypertension. Am J Respir Crit Care Med 1995;151:384–9. [22] Morales-Blanhir J, Santos S, de Jover L, et al. Clinical value of vasodilator test with inhaled nitric oxide for predicting long-term response to oral vasodilators in pulmonary hypertension. Respir Med 2004;98:225–34. [23] Cockrill BA, Kacmarek RM, Fifer MA, et al. Comparison of effects of nitric oxide, nitroprusside, and nifedipine on hemodynamics and right ventricular contractility in patient with chronic pulmonary hypertension. Chest 2001;119: 128–36. [24] Atz AM, Adatia I, Lock JE, et al. Combined effects of nitric oxide and oxygen during acute pulmonary vasodilator testing. J Am Coll Cardiol 1999;33: 813–9. [25] Rich S, Kaufmann E, Levy PS. The effect of high doses of calcium-channel blockers on survival in primary pulmonary hypertension. N Engl J Med 1992;327:76. [26] Auger WR, Fedullo PF, Moser KM, et al. Chronic major-vessel thromboembolic pulmonary artery obstruction: appearance at angiography. Radiology 1992;182:393–8. [27] Peterson KL, Fred HL, Alexander JK. Pulmonary arterial webs: a new angiographic sign of previous thromboembolism. N Engl J Med 1967;277:33. [28] Haas A, Stiehm R. Takayasu’s arteritis presenting as pulmonary hypertension. Am J Dis Child 1986; 140:372–4. [29] Cho SR, Tisnado J, Cockrell CH, et al. Angiographic evaluation of patients with unilateral massive perfusion defects in the lung scan. Radiographics 1987;7:729–45.
415
[30] Arnett EN, Bacos JM, Macher AM, et al. Fibrosing mediastinitis causing pulmonary arterial hypertension without pulmonary venous hypertension. Am J Med 1977;63:634–43. [31] Carlin BW, Moser KM. Pulmonary artery obstruction due to malignant fibrous histiocytoma. Chest 1987;92:173–5. [32] Schermoly M, Overman J, Pingleton SK. Pulmonary artery sarcoma—unusual pulmonary angiographic findings—a case report. Angiology 1987;38: 617–21. [33] Dalen JE, Banas JS, Brooks HL, et al. Resolution rate of acute pulmonary embolism in man. N Engl J Med 1969;280:1194–9. [34] Peterson KL, Nicod P. Cardiac catheterization: methods, diagnosis, and therapy. In: Shure D, Auger W, Moser K, et al, editors. Pulmonary angioscopy. Philadelphia: W.B. Saunders; 1997. p. 257–65. [35] Shure D, Gregoratos G, Moser KM. Fiberoptic angioscopy: role in the diagnosis of chronic pulmonary arterial obstruction. Ann Intern Med 1985;103:844–50. [36] Ricou F, Nicod PH, Moser KM, et al. Catheterbased intravascular ultrasound imaging of chronic thromboembolic pulmonary disease. Am J Cardiol 1991;67:749–52. [37] Kim NHS, Fesler P, Channick RN, et al. Preoperative partitioning of pulmonary vascular resistance correlates with early outcome after thromboendarterectomy for chronic thromboembolic pulmonary hypertension. Circulation 2004; 109:18–22. [38] Bonderman D, Fleischmann D, Mathias P, et al. Left main coronary artery compression by the pulmonary trunk in pulmonary hypertension. Circulation 2002;105:265.
Cardiac catheterization techniques in pulmonary hypertension Paulo Guillinta, MD, Kirk L. Peterson, MD, Ori Ben-Yehuda, MD* Division of Cardiology, Department of Medicine, University of California, San Diego, 200 West Arbor Drive, San Diego, CA 92110, USA
Once considered dangerous and potentially life threatening, cardiac catheterization of the patient with pulmonary hypertension can be performed safely and provides essential information in the diagnosis and management of pulmonary hypertension. This article summarizes the modern techniques used for right-heart catheterization, selective pulmonary angiography, and pulmonary angioscopy in the evaluation of the patient with pulmonary hypertension or with suspected chronic thromboembolic disease. Cardiac catheterization of the patient with suspected pulmonary hypertension is essential to determine accurately the cause and extent of disease. In patients with suspected chronic thromboembolic pulmonary hypertension (CTEPH), pulmonary angiography remains an essential part of the diagnostic evaluation and selection of appropriate patients for surgical pulmonary thrombendarterectomy. Although historically pulmonary angiography has been considered contraindicated in the presence of severe pulmonary hypertension, advances in cardiac and pulmonary angiographic techniques allow this procedure to be performed in a safe manner with acceptable risk. In reviewing the technique of right-heart catheterization, pulmonary angiography, and angioscopy in the patient with pulmonary hypertension, the authors draw on the experience of more than 20 years of catheterization of patients with severe pulmonary hypertension at the University of California, San Diego (UCSD) Medical Center,
* Corresponding author. E-mail address: [email protected] (O. Ben-Yehuda).
where more than 2500 such procedures have been performed.
Indications and considerations for catheterization of the patient with pulmonary hypertension Catheterization plays an integral part in the evaluation of the patient with pulmonary hypertension. The primary goals of catheterization are to determine right ventricular and pulmonary artery hemodynamics, to exclude left-to-right cardiac shunts and any significant left-sided cardiac disorder, to assist in the determination of the cause of pulmonary hypertension, and to test the response of therapeutic agents. In patients with suspected CTEPH, pulmonary angiography and angioscopy are used to assess clot location, extent, and size to determine candidacy for pulmonary thrombendarterectomy.
Safety considerations Early case reports [1–4] of fatalities associated with pulmonary angiography in patients with pulmonary hypertension have led to a lingering perception that the procedure is associated with considerable risk, primarily because of acute right ventricular failure and arrhythmias. Even rightheart catheterization alone [5] was reported to be potentially dangerous. Larger series have since been published, both in acute and chronic pulmonary embolism and in mild as well as severe pulmonary hypertension. Mills et al [6] described three deaths in 1350 patients (incidence of 0.2%), all of whom had right ventricular end diastolic pressure of 20 mm Hg or higher. Nicod et al [7]
0733-8651/04/$ - see front matter Ó 2004 Elsevier Inc. All rights reserved. doi:10.1016/j.ccl.2004.04.011
402
P. Guillinta et al / Cardiol Clin 22 (2004) 401–415
reported on the original series of 67 patients from UCSD undergoing CTEPH evaluation. Mean pulmonary arterial pressures (PAPs) were 47 13 mm Hg, with a right ventricular end diastolic pressure of 13 6 mm Hg and a cardiac index of 2.2 0.7 L/min. There were no deaths attributable to CTEPH. By 1991 this series had expanded to include more than 300 patients, without a death. Since then right-heart catheterization and pulmonary angiography have been performed in approximately 200 patients with severe pulmonary hypertension annually at UCSD, without a death related to the procedure (more than 2500 patients to date). There thus are no absolute contraindications to pulmonary angiography, and the procedure can be performed safely, provided certain precautions and advances in technique are employed. Nonfatal adverse reactions include transient hypotension and general catheterization-related adverse events such as inadvertent arterial puncture, oversedation, pneumothorax, and contrast agent–related nephropathy [8]. To minimize these risks, the authors use the following procedures at UCSD [9]: 1. Before the procedure echocardiography is performed, detecting potential clots in the right atrium or right ventricle or the presence of an atrial septal defect/patent foramen ovale. 2. Heart rate, rhythm, oxygen saturation, and systemic and PAP should be continuously monitored. Supplemental oxygen is provided to maintain oxygen saturation over 90%. 3. Access to the pulmonary vessels through the neck is preferred to avoid potential dislodgement of unsuspected venous thrombi involving the femoral vein, iliac vein, or inferior vena cava and to facilitate angioscopy. The authors prefer the internal jugular vein to the subclavian vein to reduce the risk of pneumothorax, which is likely to be poorly tolerated in these patients who are often hypoxemic. 4. Hemodynamics are assessed using a balloon flotation catheter (Swan-Ganz catheter), at times stiffened with a 0.025-cm guide wire. This stiffening greatly facilitates the catheterization in these patients, who frequently have enlarged right ventricles, significant tricuspid regurgitation, severely elevated PAPs, and low cardiac output. CO2 is used for balloon inflation to minimize the possi-
5.
6.
7.
8.
bility of paradoxical embolism in case of balloon rupture. A stiff, side-hole catheter such as a 7-F or 8-F NIH or Berman catheter is most commonly used to inject the pulmonary arteries. The injection through the side holes allows good opacification with reduced injection velocity and pressure. Catheter retraction and whipping during injection are also minimized. Unilateral, sequential injection of the contrast agent in to each main pulmonary artery is preferred. Injection into the right atrium or right ventricle is avoided, thereby eliminating the possibility of intramyocardial injection. The catheter is positioned near the origin of the lower lobe vessels, and the contrast agent is allowed to fill the upper lobes in retrograde fashion. Non-ionic contrast is preferred because fewer adverse reactions and minimal hemodynamic compromise are experienced [10,11]. Cardiac output and speed of run-off during small hand injection are used to determine the amount of contrast agent needed for assessment of the pulmonary vasculature anatomy. A smaller amount of contrast material is needed in patients with slow run-off or low cardiac output. At UCSD, the total amount of contrast medium used ranges from 20 to 65 mL. The usual injection is of 55 mL at a rate of 22 mL/second, with adjustments based on the patient’s cardiac output, assessment of the pulmonary vasculature during the hand injection, and pulmonary pressures. For example, the total occlusion of the main descending pulmonary artery after the takeoff of the upper lobe branch would necessitate a reduction of the total contrast to approximately 20 mL. Conversely, the presence of a brisk runoff during the hand injection coupled with a high cardiac output would lead to injection of more than the standard 55 mL.
Right-heart catheterization Evaluation of hemodynamics by right-heart catheterization plays an integral part of the evaluation of patients with pulmonary hypertension. The goals of right-sided catheterization are (1) to measure PAP directly and estimate pulmonary vascular resistance, (2) to evaluate for left-toright shunts, and (3) to test the response to therapeutic agents.
P. Guillinta et al / Cardiol Clin 22 (2004) 401–415
During right-heart catheterization by balloon flotation catheter, rapid determination and continuous monitoring of pressures in the right ventricle, right atrium, and pulmonary artery and of postcapillary wedge pressure are possible. Understanding of normal and pathologic pressure waveforms is important to recognize certain cardiac disorders such as valvular and pericardial disease. In patients with primary pulmonary hypertension (PPH), particular attention should be paid to the right atrial pressure and right ventricle end-diastolic pressure. In the National Heart Lung and Blood Institute registry, mean right atrial pressure and decreased cardiac index were the most important predictive variables for survival in patients with PPH [12]. The patient with PPH commonly has elevated right atrial pressure, elevated mean PAP, reduced cardiac index, and low or normal postcapillary wedge pressure [8]. A postcapillary wedge pressure is obtained with an end-hole catheter positioned in a side branch of the pulmonary artery facing a pulmonary capillary bed. One pitfall to avoid is wedging the balloon too proximally, creating a hybrid tracing of pressures between actual PAP and postcapillary wedge pressure, resulting in an overestimation of the postcapillary wedge pressure (Fig. 1). Deflating the balloon to decrease its size will allow the catheter to be wedged in a smaller, more distal branch of the pulmonary artery. Caution should be taken to avoid overwedging and possible pulmonary artery rupture, a potentially lethal event. Fortunately in pulmonary hypertension the thickened, hypertrophied arterial wall provides some protection against rupture. When it is not clear whether a wedge tracing has been obtained, a blood sample is obtained through the distal port. In the wedge position arterial saturation should be present as blood from the capillary bed is aspirated. The authors have also found that typically the more narrow, tapering anatomy of the left pulmonary artery allows more reliable wedge determinations. The use of a J-tipped 0.25 wire to guide the Swan-Ganz catheter to the left pulmonary artery is essential. Typically patients with either PPH or CTEPH have low to normal wedge pressures. In the presence of substantially elevated postcapillary wedge pressure, left-heart catheterization should be performed to exclude pulmonary venoocclusive disease, mitral stenosis, or left ventricular dysfunction. Cardiac output is best determined by the Fick method in the setting of low cardiac output states or when there is significant tricuspid regurgita-
403
tion. This method requires measuring oxygen consumption directly, because estimations of oxygen consumption may not apply to seriously ill patients with pulmonary hypertension and may introduce significant calculation errors. In experienced hands, however, determination of cardiac output by thermodilution techniques is usually satisfactory for the adjustment of therapy in these patients [13].
Response of vasodilator challenge in the cardiac catheterization laboratory Vasoconstriction of the pulmonary vessels is one of the prominent pathologic features seen in patients with pulmonary hypertension of any cause, particularly in those with PPH [14]. Unfortunately, no hemodynamic or demographic characteristics exist to predict which patients are likely to benefit from long-term vasodilator therapy [15,16]. In more recent studies, Groves et al [17] illustrated that the initial response to vasodilatory therapy accurately predicts the patient with PPH who is likely to benefit from long-term oral therapy. In addition, patients who demonstrate a reduction in total pulmonary resistance index of more than 50% in response to short-term epoprostenol (prostacyclin, PGI2) challenge at the time of diagnosis had longer disease evolutions and better prognoses than patients with a lower vasodilator response [18,19]. For these reasons [3], it is important to assess the response to vasodilator therapy in patients with PPH in the cardiac catheterization laboratory. Nitric oxide and PGI2 are useful drugs to test pulmonary vasoreactivity because they are potent, short acting, and can be titrated. The acute effects of inhaled nitric oxide and PGI2 on pulmonary artery pressure are similar [20,21]. Inhaled nitric oxide more consistently reflects the changes in pulmonary vascular tone and seems to be the better predictor of the long-term response to oral vasodilator treatment, making it the preferred agent for assessing pulmonary vasoreactivity [22]. Nitroprusside has fallen out of favor for assessing pulmonary vasoreactivity in patients with chronic pulmonary hypertension because this drug causes systemic hypotension compared with nitric oxide, at doses that cause similar degrees of pulmonary vasodilation [23]. Pulmonary arterial pressures, right ventricular pressures, cardiac output, and postcapillary wedge pressure are recorded during infusions of inhaled
404
P. Guillinta et al / Cardiol Clin 22 (2004) 401–415
Fig. 1. (A) Hybrid tracing of pulmonary artery pressure and wedge tracing overestimating wedge pressure. (B) Actual pulmonary capillary wedge pressure tracing once the balloon is deflated and allowed to wedge in a smaller, more distal branch of the pulmonary artery.
P. Guillinta et al / Cardiol Clin 22 (2004) 401–415
nitric oxide. Administration of inhaled nitric oxide with oxygen seems to be safe and provides additional pulmonary vasodilation in this patient population [24]. Pulmonary pressure are recorded during administration of 100% oxygen and inhaled nitric oxide dosed at 20 to 80 parts per million. The authors typically administer nitric oxide for 10 minutes, with repeat recordings obtained during the final 5 minutes of the inhalation. Although a mild reduction in pulmonary vascular resistance (<20%) can be seen in most patients, even those with CTEPH, significant reductions of more than 20% are seen in only one fourth of patients [25]. Pulmonary angiography: anatomy Accurate evaluation of the pulmonary angiogram requires knowledge of the pulmonary vas-
405
culature anatomy (Figs. 2 and 3). The main pulmonary artery arises from the pulmonary conus of the right ventricle, anterior and to the left of the aorta. It takes a posteromedial direction until its bifurcation into the right and left pulmonary arteries. The right pulmonary artery courses anterior to the right mainstem bronchus. It gives rise to the right upper lobe branch within the mediastinum. The left pulmonary artery passes over the left mainstem bronchus and descends posterior to the bronchus before the origin of the left upper lobe branch. The vessels then branch and are closely related to bronchial branching within the lung. Angiographic films are taken using anteroposterior and lateral projections. The lateral projection is particularly helpful in separating the overlapping tributaries of the right middle and right lower lobe and left lingual and left lower lobe. It also allows a clear separation
Fig. 2. (A) Anteroposterior view of the anatomy of the right pulmonary artery. (B) Lateral view. (Reproduced from Peterson KL, Nicod P. Catheterization and angiography in pulmonary hypertension. In: Shure D, Auger W, Moser K, et al, editors. Cardiac catheterization: methods, diagnosis, and therapy. Philadelphia: W.B. Saunders; 1977. p. 404; with permission.)
406
P. Guillinta et al / Cardiol Clin 22 (2004) 401–415
Fig. 3. Anatomy of the left pulmonary artery in (A) anteroposterior and (B) lateral views. (Reproduced from Peterson KL, Nicod P. Catheterization and angiography in pulmonary hypertension. In: Shure D, Auger W, Moser K, et al, editors. Cardiac catheterization: methods, diagnosis, and therapy. Philadelphia: W.B. Saunders; 1977. p. 405; with permission).
between the superior segmental artery and the artery to the middle lobe.
Pulmonary angiography: interpretation in the patient with pulmonary hypertension Pulmonary angiography of the patient with pulmonary hypertension plays a central role in delineating the precapillary cause of elevated pulmonary pressures. Distinguishing major-vessel from small-vessel disease allows the correct therapeutic approach to be determined. Auger et al [26] described the angiographic patterns seen in patients with chronic thromboembolic disease. These patterns include pouching abnormalities, vascular webs or bandlike constrictions, intimal irregularities, abrupt narrowing of
major pulmonary vessels, and obstruction of major pulmonary vessels, most commonly at points of origin (Figs. 4–8). Although pulmonary arterial webs are typically seen in patients with chronic thromboemboli, they are also seen in congenital stenotic lesions of the pulmonary vessels and with vasculitides such as Takayasu’s arteritis [27,28]. Patients with congenital stenotic lesions of the pulmonary vasculature present at an early age and typically have coexisting cardiac abnormalities. Most Takayasu patients with pulmonary vessel involvement demonstrate systemic manifestations. Total obstruction or abrupt narrowing of the pulmonary vessel, typically seen in chronic thromboemboli, can also be seen in extrinsic compression from extensive mediastinal or hilar lymphadenopathy, fibrosing mediastinitis, and pulmonary
P. Guillinta et al / Cardiol Clin 22 (2004) 401–415
407
Fig. 4. (A) The anteroposterior view of the right pulmonary artery in a patient with CTEPH. Note the marked hypovascularity, irregularity of the main descending pulmonary artery, and complete occlusion of most segmental branches. (B) The lateral view of the artery shown in 4A. Note the separation of the right middle lobe branches from the right lower lobe segments. In this view the middle lobe is perfused, as is the superior segment.
vascular or primary lung malignancies [29–32]. Chest CT aids in making the distinguishing these entities from chronic thromboembolic disease. Occasionally, several vascular abnormalities occur in the same patient. In this scenario, the pulmonary angiogram may aid in identifying the
Fig. 5. Right pulmonary angiogram shows central pulmonary artery enlargement and pouching abnormality in the right lower lobe vessel seen in chronic thromboembolic disease.
patient with acute on chronic thromboembolic disease (Fig. 9). Sharply defined luminal defects are seen in small, acute emboli. Proximal pulmonary artery enlargement and bandlike abnormalities are typically seen in chronic thromboembolic disease but not in acute embolic disease. The hemodynamic data can also assist in distinguishing chronic from acute embolism. Pulmonary hypertension with mean PAPs above 35 mm Hg suggest chronicity, because the right ventricle in acute pulmonary embolism without previous pulmonary hypertension is incapable of generating such high pulmonary pressures [33]. The classic angiographic findings in patients with PPH include normal or dilated central arteries with pruning of the small, more distal, nonelastic arteries [8]. Pruning of the pulmonary vessels may also be seen with chronic thromboembolic disease, but in this scenario pruning is regional and more proximal [34]. A key question that the pulmonary angiogram addresses in patients with suspected CTEPH is the extent and surgical accessibility of chronic clot. The presence of bilateral disease and proximal involvement (main pulmonary trunks, lobar arteries, and segmental arteries) predicts surgical accessibility. Correlation with findings on the perfusion scan is essential, because the presence
408
P. Guillinta et al / Cardiol Clin 22 (2004) 401–415
Fig. 6. (A) Anteroposterior view of the right pulmonary artery demonstrating hypoperfusion of the lower lobe. (B) Only on the lateral film does the extent of occlusion of the posterior basal segment and narrowing of the middle lobe branch become evident. The superior segment is also subtotally occluded.
of segmental defects is predictive of surgical success (see articles in this issue by Auger et al and Thistlethwaite et al).
When there is significant proximal disease (eg, complete occlusions of lobar vessels), the inter-
pretation of pulmonary angiograms is straightforward. In the UCSD experience the pulmonary angiogram is suggestive but not definitive in about 20% to 25% of cases. The recanalization of chronic clot allows contrast to permeate through the lesions, and the pulmonary angiogram can underestimate disease just as the perfusion scan can. In addition, the presence of defects at the
Fig. 7. Abrupt narrowing of the pulmonary vessel seen in chronic thromboembolic disease.
Fig. 8. Anteroposterior projection shows complete obstruction of the right main pulmonary artery.
Pulmonary angioscopy
P. Guillinta et al / Cardiol Clin 22 (2004) 401–415
Fig. 9. Anteroposterior view demonstrates acute on chronic thromboemboli. Note the distinct numerous luminal filling defects (solid arrow) in a bandlike or web abnormality.
transition between segmental and subsegmental vessels may raise doubt regarding the surgical accessibility. In the patient with markedly elevated pulmonary hypertension (pulmonary vascular resistance >800 dynes/second/cm5) surgical risks rise significantly if insignificant clot is removed during surgery, leaving the patient with severe pulmonary hypertension. Fiberoptic angioscopy, developed to allow direct visualization of the interior of the central pulmonary vessels up to the segmental and sub-
409
segmental levels, is used to define surgical accessibility better in borderline cases [35,36]. The challenges entailed in performing pulmonary angioscopy include the need to maneuver through an often hypertrophied right ventricle, the wide variation in pulmonary vessel size with varying anatomic branching, the large number of branches that require visualization, and the robust collateral circulation from the bronchial circulation. At UCSD pulmonary angioscopy has progressed through several stages of development over the past 20 years. The approach has been to use a balloon system to occlude blood flow completely in the vessel that is being visualized, rather than a flushing (hemodilution) approach as has been used in the coronary circulation. Hemodilution is not practicable in the large pulmonary arteries and would entail dangerous fluid overload in these patients with right-heart failure. The angioscope presently used is a 120-cm fiberoptic device, 3 mm in diameter (Figs. 10 and 11). It can be flexed 90( at the tip allowing navigation through the pulmonary tree. The occluding balloon is attached at a modified spool-like stainless steel lip, which allows secure tying of the disposable balloons. The balloon at the distal end is inflated with carbon dioxide to protect from air embolism in case of balloon rupture, a precaution of particular importance given the elevated rightsided pressures with potential for right- to-left embolism in patients with patent foramen ovale. The balloon is connected to a syringe by a tube in the angioscope, allowing deflation during the advancement of the catheter and inflation to occlude the vessel as well as allow flotation further downstream.
Fig. 10. The pulmonary angioscope. (Courtesy of Olympus Corporation, Lake Success, NY.)
410
P. Guillinta et al / Cardiol Clin 22 (2004) 401–415
Fig. 11. Inflated balloon attached to the distal tip of the angioscope.
Because of the size of the angioscope (3 mm) an 11-F sheath is used. Although angioscopy can be accomplished from the femoral approach, it is much easier to navigate the instrument through the right ventricle using the internal jugular vein approach, particularly from the right. Two operators are needed to guide the angioscope, with one advancing and torquing the instrument and the other flexing and extending it using the built-in deflectors. Angioscopy is most helpful in defining the starting point of chronic thrombi and establishing whether they are within surgical reach. This procedure enables the examiner to determine operability of patients with chronic pulmonary thromboemboli in approximately 75% of the cases when the findings on the pulmonary angiogram are questionable [34]. A detailed map of the major pulmonary vessels can be performed safely within 20 minutes, without significant morbidity, in this patient population. The main complications encountered have been transient ventricular ectopy during transit in the ventricle and minor local bleeding from the 11-F sheath site in the neck. During the procedure the fluoroscopy images are recorded to localize the lesions seen on angioscopy and are correlated with the anatomy as defined in the pulmonary angiogram. Normal pulmonary findings are of smooth, pale white, glistening intima (Fig. 12). Bifurcations are typically round and regular in appearance. In patients with pulmonary hypertension, either primary arterial hypertension or secondary to CTEPH, the arterial walls may demonstrate small, yellowish atheroscleroticlike plaques as well as more diffuse yellowish colorations (Figs. 13 and 14). Patients with chronic thrombi have irregular pulmonary arterial walls with transluminal bands
Fig. 12. Normal bifurcation of a pulmonary artery.
and obstructive lesions and irregular vessel ostia. Thin membranes can also be visualized. At times reddish-purplish subacute thrombi can be seen, which are distinct from the white fibrotic lesions of chronic organized and recanalized clot. Small-vessel arteriopathy in patients with chronic thromboembolic pulmonary hypertension Although the main site of vasculopathy and increased resistance in CTEPH is in the large, elastic pulmonary arteries, a significant number of patients have concomitant small-vessel arteriopathy that may persist despite the removal of proximal clot. These patients are at increased risk of persistent pulmonary hypertension after pulmonary thrombendarterectomy. Severe persistent pulmonary hypertension after surgery accounts for more than one third of perioperative mortality and up to 50% of long-term deaths. Recently the pulmonary artery occlusion technique [37] has been used to attempt to partition the pulmonary resistance into an upstream component (Rup) and downstream (small arterial plus venous) component. Using a standard Swan-Ganz catheter (Edwards Lifesciences Corporation, Irvine, CA) the pulmonary pressure signal is filtered using a twopole digital low-pass filter with a cutoff at 18 Hz. A biexponential fitting of the pressure decay curve is then performed, which allows estimation of the derived occlusion pressure (Poccl). Rup is then calculated as follows: Rup mean pulmonary artery pressure Poccl ¼ ð%Þ mean pulmonary artery pressure Ppao where Ppao is the final pulmonary artery occluded pressure (wedge pressure). In patients with
P. Guillinta et al / Cardiol Clin 22 (2004) 401–415
411
Fig. 13. Angioscopic findings in CTEPH. Note the fibrotic white material with membranes, webs, and pitting.
Fig. 14. Angioscopic findings in CTEPH. Note the yellow plaque prominent in B, G, and K. Membranes, webs, and masslike fibrotic tissue can be seen.
412
P. Guillinta et al / Cardiol Clin 22 (2004) 401–415
Fig. 15. Pulmonary artery pressure occlusion waveforms from two patients with (A) mainly upstream resistance and (B) mainly downstream resistance. In A the pressure drops more rapidly with balloon occlusion, resulting in lower Poccl and higher Rup%.
small-vessel arteriopathy the Poccl pressure is higher (a longer time is required for the pressure to reach Ppao), and therefore the Rup % is lower (Fig. 15). In a study [37] of 26 patients with suspected CTEPH, there was an excellent correlation between Rup % before pulmonary thrombendarterectomy and hemodynamic response to surgery. Moreover, all four patients with Rup % below 60 did not survive surgery (Fig. 16). Coronary arteriography Before pulmonary thrombendarterectomy the authors routinely perform coronary arteriography on all male patients above the age of 40 and female patients above the age of 45 and do so for
younger patients if findings are suggestive of coronary disease. In the presence of markedly enlarged proximal pulmonary arteries, the left main pulmonary artery may become compressed and give the appearance of ostial left main stenosis [38]. Best visualized in the let anterior oblique cranial view (Fig. 17), this finding is usually devoid of other evidence of atherosclerosis and is not in itself an indication for bypass surgery, especially if the patient’s pulmonary pressures decrease after surgery. Summary Cardiac catheterization of the patient with pulmonary hypertension plays an integral part in
P. Guillinta et al / Cardiol Clin 22 (2004) 401–415
413
Fig. 16. Correlation between preoperative Rup % and postoperative outcomes. (A) Postoperative pulmonary resistance (B) Mean postoperative pulmonary pressure. (Reproduced from Kim NH, Fesler P, Channick RN, et al. Preoperative pulmonary partitioning of pulmonary vascular resistance correlates with early outcome after thromboendarterectomy for chronic thromboembolic pulmonary hypertension circulation. 2004;109:19; with permission.)
414
P. Guillinta et al / Cardiol Clin 22 (2004) 401–415
Fig. 17. Left main ostial compression from an enlarged pulmonary artery. (Reproduced from Bonderman D, Fleischmann D, Prokop M, et al. Imges in cardiovascular medicine. Left main coronary artery compression by the pulmonary trunk in pulmonary hypertension. Circulation 2002;105:265; with permission.)
the diagnostic evaluation. Right-heart hemodynamics, pulmonary angiography, and pulmonary angioscopy offer a way to determine the cause of disease safely and accurately and to offer potentially life-saving therapies.
References [1] Dotter CT, Jackson FS. Death following angiocardiography. Radiology 1950;54:527–33. [2] Diamond EG, Gonlubol F. Death following angiocardiography: report of two cases after administration of diodrast and neo-iopax, respectively. N Engl J Med 1953;249:1029–31. [3] Alexander JK, Gonzales DA, Fred HL. Angiographic studies in cardiorespiratory diseases: special reference to thromboembolism. JAMA 1966;198: 575–8. [4] Snider GL, Ferris E, Gaensler EA, et al. Primary pulmonary hypertension: a fatality during pulmonary angiography. Chest 1973;64:628–35. [5] Caldini P, Gensini GG, Hoffman MS. Primary pulmonary hypertension with death during right heart catheterization. Am J Cardiol 1959;519–27. [6] Mills SR, Jackson DC, Older RA, et al. The incidence, etiologies, and avoidance of complications of pulmonary angiography in a large series. Radiology 1980;136:295–9. [7] Nicod P, Peterson KL, Levine M, et al. Pulmonary angiography in severe chronic pulmonary hypertension. Ann Intern Med 1987;107:565–8. [8] Rich S, Dantzker DR, Ayres SM, et al. Primary pulmonary hypertension: a national prospective study. Ann Intern Med 1987;107:216–23.
[9] Peterson KL, Nicod P. Catheterization and angiography in pulmonary hypertension. In: Shure D, Auger W, Moser K, et al, editors. Cardiac catheterization: methods, diagnosis, and therapy. Philadelphia: W.B. Saunders; 1977. p. 401–14. [10] Kumazaki T. Ioxaglate versus diatrizoate in selective pulmonary angiography. Part II: cardiovascular responses. Acta Radiol 1985;26:635. [11] Smith DC, Lois JF, Gomes AS, et al. Pulmonary angiography: comparison of cough stimulation effects of diatrizoate and ioxaglate. Radiology 1987; 162:617–8. [12] D’Alonzo GE, Barst RJ, Ayres SM, et al. Survival in patients with primary pulmonary hypertension: result from a national prospective registry. Ann Intern Med 1991;115:343–9. [13] Rubin LW, Rich S. Primary pulmonary hypertension. In: Georgiou D, Cao T, Shapiro S, et al, editors. Hemodynamic evaluation in primary pulmonary hypertension. New York: Marcel Dekker; 1997. p. 253–86. [14] Wagenvoort CA. Vasoconstriction and medial hypertrophy in pulmonary hypertension. Circulation 1960;22:535–46. [15] Weir EK, Rubin LJ, Ayres SM, et al. The acute administration of vasodilator therapy in primary pulmonary hypertension: experience from the National Institute of Health Registry on Primary Pulmonary Hypertension. Am Rev Resp Dis 1989; 140:1623–40. [16] Weir EK. Acute vasodilator testing and pharmacological treatment of primary pulmonary hypertension. In: Fishman AP, editor. The pulmonary circulation: normal and abnormal: mechanisms, management and the national registry. Philadelphia: University of Pennsylvania Press; 1990. p. 485–99. [17] Groves BM, Badesch DB, Turkevich D, et al. Correlation of acute prostacyclin response in primary (unexplained) pulmonary hypertension with efficacy of treatment with calcium channel blockers and survival. In: Hummes JR, Reeves JT, Weir EK, editors. Ion flux in pulmonary vascular control. New York: Plenum Press; 1993. p. 317–30. [18] Rich S, Brundage BH. High-dose calcium channelblocking therapy for primary pulmonary hypertension: evidence of long-term reduction in pulmonary arterial hypertension and regression of right ventricular hypertrophy. Circulation 1987;76:135–41. [19] Olivier R, Re´za A, Franc¸ois B, et al. Clinical significance of the pulmonary vasodilator response during short-term infusion of prostacyclin in primary pulmonary hypertension. Circulation 1996; 93:484–8. [20] Rich S, Kaufmann E, Levy PS. The effects of high doses of calcium-channel blocker on survival in primary pulmonary hypertension. N Engl J Med 1992;327:76–81.
P. Guillinta et al / Cardiol Clin 22 (2004) 401–415 [21] Sitbon O, Brenot F, Denjean A, et al. Inhaled nitric oxide as a screening vasodilator agent in primary pulmonary hypertension. Am J Respir Crit Care Med 1995;151:384–9. [22] Morales-Blanhir J, Santos S, de Jover L, et al. Clinical value of vasodilator test with inhaled nitric oxide for predicting long-term response to oral vasodilators in pulmonary hypertension. Respir Med 2004;98:225–34. [23] Cockrill BA, Kacmarek RM, Fifer MA, et al. Comparison of effects of nitric oxide, nitroprusside, and nifedipine on hemodynamics and right ventricular contractility in patient with chronic pulmonary hypertension. Chest 2001;119: 128–36. [24] Atz AM, Adatia I, Lock JE, et al. Combined effects of nitric oxide and oxygen during acute pulmonary vasodilator testing. J Am Coll Cardiol 1999;33: 813–9. [25] Rich S, Kaufmann E, Levy PS. The effect of high doses of calcium-channel blockers on survival in primary pulmonary hypertension. N Engl J Med 1992;327:76. [26] Auger WR, Fedullo PF, Moser KM, et al. Chronic major-vessel thromboembolic pulmonary artery obstruction: appearance at angiography. Radiology 1992;182:393–8. [27] Peterson KL, Fred HL, Alexander JK. Pulmonary arterial webs: a new angiographic sign of previous thromboembolism. N Engl J Med 1967;277:33. [28] Haas A, Stiehm R. Takayasu’s arteritis presenting as pulmonary hypertension. Am J Dis Child 1986; 140:372–4. [29] Cho SR, Tisnado J, Cockrell CH, et al. Angiographic evaluation of patients with unilateral massive perfusion defects in the lung scan. Radiographics 1987;7:729–45.
415
[30] Arnett EN, Bacos JM, Macher AM, et al. Fibrosing mediastinitis causing pulmonary arterial hypertension without pulmonary venous hypertension. Am J Med 1977;63:634–43. [31] Carlin BW, Moser KM. Pulmonary artery obstruction due to malignant fibrous histiocytoma. Chest 1987;92:173–5. [32] Schermoly M, Overman J, Pingleton SK. Pulmonary artery sarcoma—unusual pulmonary angiographic findings—a case report. Angiology 1987;38: 617–21. [33] Dalen JE, Banas JS, Brooks HL, et al. Resolution rate of acute pulmonary embolism in man. N Engl J Med 1969;280:1194–9. [34] Peterson KL, Nicod P. Cardiac catheterization: methods, diagnosis, and therapy. In: Shure D, Auger W, Moser K, et al, editors. Pulmonary angioscopy. Philadelphia: W.B. Saunders; 1997. p. 257–65. [35] Shure D, Gregoratos G, Moser KM. Fiberoptic angioscopy: role in the diagnosis of chronic pulmonary arterial obstruction. Ann Intern Med 1985;103:844–50. [36] Ricou F, Nicod PH, Moser KM, et al. Catheterbased intravascular ultrasound imaging of chronic thromboembolic pulmonary disease. Am J Cardiol 1991;67:749–52. [37] Kim NHS, Fesler P, Channick RN, et al. Preoperative partitioning of pulmonary vascular resistance correlates with early outcome after thromboendarterectomy for chronic thromboembolic pulmonary hypertension. Circulation 2004; 109:18–22. [38] Bonderman D, Fleischmann D, Mathias P, et al. Left main coronary artery compression by the pulmonary trunk in pulmonary hypertension. Circulation 2002;105:265.