- Email: [email protected]
No-Clamp Technique for Valve Repair or Replacement in Patients With a Porcelain Aorta
CARDIOVASCULAR
No-Clamp Technique for Valve Repair or Replacement in Patients With a Porcelain Aorta Leonard N. Girardi, MD, Karl H. Krieger, MD, Charles A. Mack, MD, and O. Wayne Isom, MD Department of Cardiothoracic Surgery, Weill Medical College of Cornell University, New York, New York
Background. Patients requiring valvular heart surgery may have circumferential calcification of the ascending aorta. A variety of creative procedures have been described for managing this “porcelain aorta.” We describe a technique based on replacement of the ascending aorta and proximal arch under profound hypothermic circulatory arrest, followed by the valve procedure. Methods. Twenty-five consecutive patients with a porcelain aorta were referred for heart valve surgery. In every case the aorta was replaced under circulatory arrest before the valve procedure. Postoperative morbidity, mortality, and univariate risk factors for death were calculated. Fisher’s exact test defined significant perioperative variables with a p value less than 0.05. Results. Of 25 patients, 23 (92%) survived the surgery to hospital discharge. One patient had a stroke (4%) and
2 patients (8%) required reexploration for bleeding. Risk factors for perioperative death by univariate analysis included age more than 78 years (p < 0.009), cardiopulmonary bypass time longer than 200 minutes (p < 0.0001), reexploration for bleeding (p < 0.02), need for intra-aortic balloon pump support (p < 0.001), and postoperative gastrointestinal complications (p < 0.001). Conclusions. Valve replacement or repair in the patient with a porcelain aorta can be safely accomplished with a technique based on aortic replacement under circulatory arrest. Elderly patients requiring extensive procedures and prolonged periods on bypass have a substantially increased risk for postoperative complications and death.
A
been described for dealing with the severely diseased ascending aorta [6 –11]. An earlier report on 540 patients with atherosclerotic aortas described a small subset of patients having aortic replacement under PHCA [2]. The operative mortality for this cohort was 10% with a small risk of CVA despite a high percentage of patients having significant carotid artery disease. Encouraged by these results, we adopted this technique of aortic replacement before valve replacement or repair in a consecutive series of patients requiring valvular heart surgery in the setting of a truly porcelain aorta. We report our contemporary experience with this aggressive technique, modified by the addition of retrograde cerebral perfusion and high mean arterial pressure cardiopulmonary bypass [12, 13].
pproximately 2% of patients requiring cardiac surgery will have extreme calcification of the ascending aorta and aortic arch [1–3]. The presence of dense, circumferential calcification of the ascending aorta, a “porcelain aorta,” complicates the intraoperative management of patients requiring cardiac surgery. Traditional methods of cardiopulmonary bypass and aortic cross-clamping increase the risk of cerebral embolization and cerebrovascular accident (CVA) to unacceptable levels [1]. Over the last 2 decades, a number of creative methods have been described for dealing with these high-risk patients. In patients with isolated coronary artery disease, off-pump coronary artery bypass, sometimes performed with alternative sites for proximal graft inflow, has been well described [4]. Proximal graft connectors have also eliminated the need for aortic manipulation [5]. Although the long-term patency of bypass grafts in this setting has yet to be determined, these operations can be performed with a significant reduction in the risk of cerebral damage. Patients requiring valve replacement, however, cannot be managed with these techniques. Therefore, multiple alternative methods, including apicoaortic conduit, endoaortic balloon or Foley catheter occlusion, and aortic valve replacement under profound hypothermic circulatory arrest (PHCA), have
Accepted for publication April 25, 2005. Address correspondence to Dr Girardi, Department of Cardiothoracic Surgery, Weill Medical College of Cornell University, 525 East 68th St, M-424, New York, NY 10021; e-mail: [email protected].
© 2005 by The Society of Thoracic Surgeons Published by Elsevier Inc
(Ann Thorac Surg 2005;80:1688 –92) © 2005 by The Society of Thoracic Surgeons
Material and Methods Between July 1997 and December 2004, 25 patients were referred for valve replacement or repair in the setting of a porcelain aorta. Their demographic data are listed in Table 1. At the time of their admission, a diagnosis of porcelain aorta was confirmed by the appearance of the aorta on admission chest radiograph or on fluoroscopy at the time of cardiac catheterization. All patients then had evaluation of their entire aorta with computed tomography scanning in order to evaluate possible sites for aortic reconstruction and cannulation in the ascending aorta and aortic arch. 0003-4975/05/$30.00 doi:10.1016/j.athoracsur.2005.04.044
GIRARDI ET AL VALVE SURGERY WITH PORCELAIN AORTA
Table 1. Preoperative Demographics for 25 Patients With a Porcelain Aorta Mean age (years) Range (years) Male : female Mean ejection fraction (%) NYHA class (n) I II III IV Hypertension (n) Previous MI (n) COPD (n) Previous CVA (n) Previous OHS (n)
74.5 54–89 14 : 11 42 0 4 10 11 24 12 13 5 5
COPD ⫽ chronic obstructive pulmonary disease; CVA ⫽ cerebrovascular accident; MI ⫽ myocardial infarction; NYHA ⫽ New York Heart Association; OHS ⫽ open heart surgery.
After standard anesthetic preparation, a median sternotomy was used to expose the ascending aorta, aortic arch, and the heart. The diagnosis of porcelain aorta was confirmed by gentle digital palpation of the aorta. Soft areas devoid of plaque were noted and marked as possible sites for aortic cannulation. The aorta was then examined by epiaortic echocardiography to determine the presence or absence of mobile atheroma in the proposed region of cannulation [2]. Patients with patchy calcification that was not circumferential or in whom a cross-clamp could be applied were excluded from this cohort. In 21 patients, the ascending aorta or arch were found to have small, isolated areas devoid of calcium. These locations were deemed suitable sites for aortic cannulation. Four additional patients were found to be without a suitable site for traditional cannulation and were placed on cardiopulmonary bypass through the femoral artery. Axillary cannulation was not found to be necessary in any patient. Heparin was administered at 400 mg/kg. Bicaval venous cannulation was utilized to facilitate the administration of retrograde cerebral perfusion (RCP) during PHCA [12]. Patients were then placed on cardiopulmonary bypass and core cooled to a bladder temperature of 18°C. While on bypass, mean arterial pressure was maintained between 70 and 80 mm Hg [13]. A right superior pulmonary vein vent was placed, and the ascending aorta was not clamped. Once the appropriate temperature was reached, 1 g pentothal was administered, and PHCA was initiated with the patient in a steep Trendelenberg position. The aorta was opened, and RCP was initiated at 150 to 300 cc/min, keeping the CVP less than 25 mm Hg. Retrograde cold, blood potassium cardioplegia was given during this initial phase of the operation after PHCA was begun. The aorta was then inspected and palpated, and a suitable area for reconstruction in the proximal arch was identified. If there was no obvious break in the circum-
1689
ferential calcification in this location, a local endarterectomy was performed. Aortic reconstruction was then performed with a one-branch Dacron prosthesis (Meadox Medical, Oakland, New Jersey) and 3-0 polypropylene suture. The suture line was then reinforced with horizontal mattress pledgetted sutures. In patients requiring endarterectomy, a neoadventitia was created with Teflon (Impra, subsidiary of L.R. Bard, Tempe, Arizona) felt strips outside this area. Cardiopulmonary bypass was then reinstituted through the side branch graft and systemic warming was initiated, maintaining a 10°C gradient between the blood and core temperature. Valve replacement, repair or coronary bypass grafting, or both, was then performed after this period of PHCA. The aortic reconstruction was then completed at the level of the sinotubular junction utilizing the aforementioned techniques. Aortic root replacement was not necessary in any of the 25 patients. During this phase of aortic reconstruction, myocardial protection was achieved by antegrade direct coronary ostial injection or retrograde coronary sinus delivery. All patients were given full Hammersmith dose aprotonin (6 million units), and blood product replacement was utilized as necessary. Postoperative hematocrit was maintained above 30%, and systolic blood pressure was optimized to 110 mm Hg or greater. All postoperative complications were recorded, as was in-hospital mortalTable 2. Intraoperative Data and Procedures for 25 Patients With a Porcelain Aorta Number of Patients (n ⫽ 25)
Primary Procedure Primary Procedure Aortic valve replacement Mitral valve replacement Mitral valve repair Additional procedures Ascending and hemiarch replacement Coronary artery bypass Aortic endarterectomy Tricuspid valve repair Reimplantation of SVGs Operative data Arterial cannulation Aortic Femoral Mean cooling time (minutes) Mean warming time (minutes) Mean PHCA time (minutes) Range Mean cardiac ischemic time (minutes) Range Mean cardiopulmonary bypass time (minutes) Range PHCA ⫽ profound hypothermic circulatory arrest; vein grafts.
22 2 1 25 15 4 1 1
21 4 32 82 19 14–29 96 59–159 170 117–312
SVG ⫽ saphenous
CARDIOVASCULAR
Ann Thorac Surg 2005;80:1688 –92
CARDIOVASCULAR
1690
GIRARDI ET AL VALVE SURGERY WITH PORCELAIN AORTA
Ann Thorac Surg 2005;80:1688 –92
Table 3. Postoperative Morbidity and Mortality Event Reexploration for bleeding Intra-aortic balloon pump/low cardiac output Cerebrovascular accident Perioperative myocardial infarction Permanent pacemaker Superficial sternal wound infection Intubation ⬎ 48 hours Tracheostomy Ischemic bowel Intraoperative death In-hospital death
Number of Patients (n ⫽ 25) 2 1 1 0 1 1 1 0 1 0 2
ity. This study was approved by the institutional review board of the Weill Medical College of Cornell University.
Statistical Analysis A retrospective, comparative statistical analysis of perioperative variables was performed using SPSS statistical package (SPSS, Chicago, Illinois). Univariate analysis was performed with 2 analysis. Statistical significance was defined by a p value of 0.05 or less.
Results A total of 25 patients with a porcelain aorta were referred for valvular heart surgery. A majority of the patients required aortic valve replacement as their primary procedure (n ⫽ 22), whereas the remainder were referred with mitral valve disease (n ⫽ 3). The preoperative demographics for this cohort are listed in Table 1. A majority of the patients required procedures in addition to their primary valve procedure (Table 2). Sixty percent of patients required coronary revascularization, and 16% required an aortic endarterectomy to safely reconstruct the aorta in the arch or at the sinotubular junction, or both. One patient with a previous CABG required reimplantation of a patent saphenous vein graft. The other 4 with patent internal mammary artery grafts had this graft identified and controlled during the procedure to enhance myocardial protection. The patient undergoing mitral valve repair also had significant tricuspid regurgitation, and a valvuloplasty was necessary. Table 2 also demonstrates the operative details of these procedures. The majority of patients reached a core temperature of approximately 18°C by 30 minutes of systemic cooling (mean cooling time, 32 minutes). The greater range in times of systemic warming are due to the varying number of additional procedures required. No patient required a period of PHCA longer than 29 minutes. Three patients were on bypass for longer than 200 minutes, 1 requiring 312 minutes of extracorporeal circulation. Postoperative complications and mortality are highlighted in Table 3. Although 20% of patients had previous
CABG surgery and 60% of patients required additional bypass grafting, no patient had a documented myocardial infarction. In addition, despite the advanced age of the patients, none had respiratory failure requiring tracheostomy. One patient had a nonfatal CVA (left-sided weakness) and recovered full function before discharge. No patient required hemodialysis. Univariate risk factors for death following these operations are listed in Table 4. There were no intraoperative deaths. One of the 2 postoperative deaths (8%) occurred in a 79-year-old man with critical aortic stenosis, severe aortic insufficiency, a previous CABG, and an ejection fraction of 30%. He had low cardiac output after his extensive procedure (CPB time, 312 minutes) that included an aortic endarterectomy and reimplantation of patent saphenous vein grafts. He also required reexploration for postoperative hemorrhage. He subsequently died on postoperative day 6. The other death occurred in an 82-year-old woman with critical aortic stenosis, moderate aortic insufficiency, and ejection fraction of 40%. She also required two bypass grafts. Ischemic bowel developed on postoperative day 4, and she was taken for exploratory laparotomy. The entire colon and small intestine was gangrenous, and the patient was taken back to the intensive care unit and allowed to die without aggressive efforts.
Comment Patients with severe atherosclerotic disease of the aorta are at particularly high risk for stroke and death after cardiac surgery. In a review of 221 patients having cardiac procedures on cardiopulmonary bypass, Blauth and coworkers [14] found that 22% had atheroemboli, a majority being embolic events to the cerebral circulation. In patients with severe aortic atherosclerosis, the risk was greatest with 37% experiencing an embolic event. Gillinov and colleagues [15] reported their experience with a similar patient population undergoing aortic valve replacement. Utilizing a number of operative strategies to minimize the risk of cerebral embolization, they reduced the incidence of CVA in this group to 10% with a hospital mortality of 14%. Eighteen percent (n ⫽ 11) of this cohort of 62 patients had a “porcelain aorta.” This highest risk subset was also treated with a variety of methods. They, however, had a marked increase in stroke and mortality
Table 4. Univariate Risk Factors for Death After Aortic Replacement for Patients With a Porcelain Aorta p Value Preoperative variable Age ⬎ 78 years Intraoperative/postoperative variable Cardiopulmonary bypass time ⬎ 200 minutes Reexploration for hemorrhage Gastrointestinal complication Need for intra-aortic balloon pump
0.009 0.0001 0.02 0.001 0.001
(3 of 11, 27%) compared with the other patients in this series. Of the various techniques utilized, this report, like others before [2, 16], found aortic replacement under circulatory arrest to provide the least risk of cerebral injury. Patients being treated with this technique based on minimizing aortic manipulation and utilizing a short period of PHCA (mean time, 17 minutes) were spared cerebral injury. While some have been unable to duplicate the above results utilizing PHCA [17], we have embraced this approach in all our patients with significant valvular heart disease and a porcelain aorta, and believe this technique provides the cardiac surgeon with the best opportunity to treat the underlying cardiac pathology while minimizing the potential for a devastating cerebrovascular accident. Because nearly 2% of all cardiac surgery patients have severe aortic atherosclerosis [1], and approximately one fifth of this group will have the extreme “porcelain” subtype, strategies to safely manage this population are needed. Patients with a severely calcified ascending aorta who require isolated CABG may be treated with innovative methods aimed at reducing atheroemboli during the procedure. Off-pump coronary artery bypass graft surgery (OPCABG) is a safe strategy that can be performed without aortic cross-clamping and the potential for atheroembolism generated by the heart and lung machine. Alternative sites for proximal anastomoses can completely eliminate aortic manipulation and may further reduce the incidence of stroke. The evolution of proximal connector devices may offer additional benefits for patients with severely atherosclerotic aortas requiring bypass surgery [4, 5]. Patients with advanced valvular heart disease will require cardiopulmonary bypass for valve replacement or repair. In patients with a porcelain aorta and mitral insufficiency or stenosis, surgery can be safely performed without aortic cross-clamping. Recent advancements in minimally invasive mitral valve surgery have led to the development of alternative strategies for arterial cannulation, endoaortic balloon occlusion, and retrograde cardioplegia [18]. In patients without significant aortic insufficiency, hypothermic fibrillation on cardiopulmonary bypass can also provide adequate myocardial protection and valve exposure for patients not requiring concomitant coronary artery bypass [19]. Although successful outcomes utilizing either of these strategies have been reported, it may be difficult to duplicate the usually low morbidity and mortality rates with these techniques in the elderly population with a porcelain aorta. These patients often have severe atherosclerosis of the descending aorta and peripheral vasculature that can make alternative sites for arterial cannulation and endoaortic manipulation less desirable and significantly more technically challenging. Axillary artery cannulation may offer some advantages in this setting [20]. Although only 3 patients in our report had mitral valve disease as their primary cardiac pathology, we believe aortic replacement under PHCA can be safely performed with similarly good outcomes. An overwhelming majority of patients can be managed with central aortic cannulation and antegrade
GIRARDI ET AL VALVE SURGERY WITH PORCELAIN AORTA
1691
cardiopulmonary bypass, thus eliminating the possibility of retrograde embolization of debris from the descending thoracic aorta. It also reduces the incidence of retrograde aortic dissection and balloon migration that has been reported utilizing endoaortic techniques. In patients with a porcelain aorta needing mitral valve surgery, a complete evaluation of their arterial system is appropriate. That will provide the surgeon with the information necessary to choose the surgical approach they are most comfortable with for these high-risk patients. Patients in need of aortic valve replacement in the setting of a porcelain aorta are often turned down for surgery because the risk of stroke is thought to be prohibitive. However, the natural history of medically treated severe aortic valve disease, particularly aortic stenosis, is dismal. In a series of 100 symptomatic patients with critical aortic stenosis treated with medical therapy alone, there was a 33% mortality in the first year after the development of symptoms [21]. Over the last 2 decades, a number of innovative techniques have been described that have the common pathway of minimizing manipulation of the severely calcified aorta while performing aortic valve replacement under PHCA or with aortic endarterectomy. Aortic valve replacement under PHCA was first described in 1986. In 2 cases, the aortic valve was replaced during 38 and 44 minutes of circulatory arrest without neurologic injury or death [7]. A similar approach was espoused by Bryne and colleagues [22] in a 1998 report on 3 patients undergoing the same procedure. Despite a mean PHCA period of 54 minutes, the results were again excellent. Aortic endarterectomy is also useful in this setting. Svensson and colleagues [23] described 6 cases of extensive ascending aortic endarterectomy in patients requiring aortic replacement. Only 1 patient sustained a neurologic deficit, and there were no deaths. However, in the patients with a truly porcelain aorta, PHCA was still required, thus eliminating the potential advantages of this simpler technique. In addition, follow-up was quite limited, and the potential for aneurysmal degeneration of the endarterectomized aorta remains unknown. Kouchoukos’s group [2] was the first to describe aortic replacement under PHCA for patients with a porcelain aorta. Of 540 patients undergoing cardiac surgery, 10 had severe diffuse atheromatous disease and were treated with graft replacement of the ascending aorta under PHCA. The mortality rate for this procedure was 10%. There were no strokes, but 1 of the 10 patients had a transient neurologic deficit that resolved before discharge. These results were more remarkable when considering that all these patients were perfused through the femoral artery and that 3 had severe enough carotid disease to mandate concomitant endarterectomy. A follow-up report confirmed the efficacy of this approach in a larger cohort of patients [16]. A recent report in 44 patients having aortic replacement in this clinical setting revealed a stroke risk of 11% with an operative mortality of 6.8% [24]. Certainly, conclusions from any nonrandomized, retrospective analysis of a small cohort of patients should be interpreted with caution. However, we believe the results
CARDIOVASCULAR
Ann Thorac Surg 2005;80:1688 –92
CARDIOVASCULAR
1692
GIRARDI ET AL VALVE SURGERY WITH PORCELAIN AORTA
with aortic replacement under PHCA reaffirm this technique’s utility in minimizing neurologic injury. Twenty percent of our patients had previous strokes yet only 1 had a focal neurologic deficit after surgery. With replacement of the diseased aorta, there is no risk of aneurysm formation after surgery, and the risk of embolization from a calcified and diseased ascending aorta and proximal arch is eliminated. The operative mortality from this procedure, 8%, is similar to that of others performing this procedure [2, 16, 24] and correlates strongly with the need for extensive procedures and prolonged periods of cardiopulmonary bypass. Perhaps a less invasive approach dealing only with the patient’s valve disease will prove to be more efficacious for elderly patients who may not tolerate extreme intervention [25].
References 1. Mills NL, Everson CT. Atherosclerosis of the ascending aorta and coronary artery bypass. J Thorac Cardiovasc Surg 1991; 102:546 –53. 2. Wareing TH, Davila-Roman VG, Barzilai B, et al. Management of the severely atherosclerotic ascending aorta during cardiac operations. J Thorac Cardiovasc Surg 1992;103:453– 62. 3. Tobler HG, Edwards JE. Frequency and location of atherosclerotic plaques in the ascending aorta. J Thorac Cardiovasc Surg 1988;96:304 – 6. 4. Sabik JF, Gillinov AM, Blackstone EH, et al. Does off-pump coronary surgery reduce morbidity and mortality? J Thorac Cardiovasc Surg 2002;124:698 –707. 5. Gunnert JF, Bossert T, Mohr FW. The use of an aortic connector system in a patient with severely calcified ascending aorta. J Card Surg 2004;19:62– 4. 6. Cosgrove DM. Management of the calcified aorta: an alternative method of occlusion. Ann Thorac Surg 1983;36:718 –9. 7. Coselli JS, Crawford ES. Aortic valve replacement in the patient with extensive calcification of the ascending aorta (the porcelain aorta). J Thorac Cardiovasc Surg 1986;91: 184 –7. 8. Culliford AT, Colvin SB, Rohrer K, et al. The atherosclerotic ascending aorta and transverse arch. A new technique to prevent cerebral injury during bypass: experience with 13 patients. Ann Thorac Surg 1986;41:27–35. 9. Black JJM, Allan A, Williams BT. The use of foley balloon catheters in cardiac surgery. Eur J Cardiothorac Surg 1993; 7:617–9. 10. Liddicoat JR, Doty JR, Stuart RS. Management of the atherosclerotic ascending aorta with endoaortic occlusion. Ann Thorac Surg 1998;65:1133–5.
Ann Thorac Surg 2005;80:1688 –92
11. Skrabal CA, Loebe M, Thompson LO, et al. Apicoaortic conduit in a patient with severe hemolysis after three aortic valve replacements. J Thorac Cardiovasc Surg 2004;127: 270 –2. 12. Coselli JS. Retrograde cerebral perfusion via a superior vena caval cannula for aortic arch aneurysm operations. Ann Thorac Surg 1994;57:1668 –9. 13. Gold JP, Charlson ME, Williams-Russo P, et al. Improvement of outcomes after coronary artery bypass: a randomized trial comparing intraoperative high versus low mean arterial pressure. J Thorac Cardiovasc Surg 1995;110:1302–14. 14. Blauth CI, Cosgrove DM, Webb BW, et al. Atheroembolism from the ascending aorta: an emerging problem in cardiac surgery. J Thorac Cardiovasc Surg 1992;103:1104 –12. 15. Gillinov AM, Lytle BW, Hoang V, et al. The atherosclerotic aorta at aortic valve replacement: surgical strategies and results. J Thorac Cardiovasc Surg 2000;120:957– 65. 16. Kouchoukos NT, Wareing TH, Daily BB, et al. Management of the severely atherosclerotic aorta during cardiac operations. J Card Surg 1994;9:490 – 4. 17. King RC, Kanithanon RC, Shockey KS, et al. Replacing the atherosclerotic ascending aorta is a high-risk procedure. Ann Thorac Surg 1998;66:396 – 401. 18. Reichenspurner H, Detter C, Deuse T, et al. Video and robotic-assisted minimally invasive mitral valve surgery: a comparison of the port-access and transthoracic clamp techniques. Ann Thorac Surg 2005;79:485–91. 19. Calleja F, Martinez JL, Gonzales De Vega N. Mitral valve surgery through a right thoracotomy. J Cardiovasc Surg 1996;37(Suppl 1):49 –52. 20. Baribeau RY, Westbrook BM, Charlesworth DC, et al. Arterial inflow via an axillary artery graft for the severely atheromatous aorta. Ann Thorac Surg 1998;66:33–7. 21. Rosenhek R, Binder T, Porenta G, et al. Predictors of outcome in severe asymptomatic aortic stenosis. N Engl J Med 2000;343:611–7. 22. Byrne JG, Aranki SF, Cohn LH. Aortic valve operations under deep hypothermic circulatory arrest for the porcelain aorta: “no-touch” technique. Ann Thorac Surg 1998:65: 1313–5. 23. Svensson LG, Sun J, Cruz HA, et al. Endarterectomy for calcified porcelain aorta associated with aortic valve stenosis. Ann Thorac Surg 1996;61:149 –52. 24. Aranki SF, Nathan M, Shekar P, et al. Hypothermic circulatory arrest enable aortic valve replacement in patients with unclampable aorta. Society of Thoracic Surgery, Plenary Session, Tampa, Florida, January 2005. 25. Lutter G, Ardehali R, Cremer J, et al. Percutaneous valve replacement: current state and future prospects. Ann Thorac Surg 2004;78:2199 –206.
No-Clamp Technique for Valve Repair or Replacement in Patients With a Porcelain Aorta Leonard N. Girardi, MD, Karl H. Krieger, MD, Charles A. Mack, MD, and O. Wayne Isom, MD Department of Cardiothoracic Surgery, Weill Medical College of Cornell University, New York, New York
Background. Patients requiring valvular heart surgery may have circumferential calcification of the ascending aorta. A variety of creative procedures have been described for managing this “porcelain aorta.” We describe a technique based on replacement of the ascending aorta and proximal arch under profound hypothermic circulatory arrest, followed by the valve procedure. Methods. Twenty-five consecutive patients with a porcelain aorta were referred for heart valve surgery. In every case the aorta was replaced under circulatory arrest before the valve procedure. Postoperative morbidity, mortality, and univariate risk factors for death were calculated. Fisher’s exact test defined significant perioperative variables with a p value less than 0.05. Results. Of 25 patients, 23 (92%) survived the surgery to hospital discharge. One patient had a stroke (4%) and
2 patients (8%) required reexploration for bleeding. Risk factors for perioperative death by univariate analysis included age more than 78 years (p < 0.009), cardiopulmonary bypass time longer than 200 minutes (p < 0.0001), reexploration for bleeding (p < 0.02), need for intra-aortic balloon pump support (p < 0.001), and postoperative gastrointestinal complications (p < 0.001). Conclusions. Valve replacement or repair in the patient with a porcelain aorta can be safely accomplished with a technique based on aortic replacement under circulatory arrest. Elderly patients requiring extensive procedures and prolonged periods on bypass have a substantially increased risk for postoperative complications and death.
A
been described for dealing with the severely diseased ascending aorta [6 –11]. An earlier report on 540 patients with atherosclerotic aortas described a small subset of patients having aortic replacement under PHCA [2]. The operative mortality for this cohort was 10% with a small risk of CVA despite a high percentage of patients having significant carotid artery disease. Encouraged by these results, we adopted this technique of aortic replacement before valve replacement or repair in a consecutive series of patients requiring valvular heart surgery in the setting of a truly porcelain aorta. We report our contemporary experience with this aggressive technique, modified by the addition of retrograde cerebral perfusion and high mean arterial pressure cardiopulmonary bypass [12, 13].
pproximately 2% of patients requiring cardiac surgery will have extreme calcification of the ascending aorta and aortic arch [1–3]. The presence of dense, circumferential calcification of the ascending aorta, a “porcelain aorta,” complicates the intraoperative management of patients requiring cardiac surgery. Traditional methods of cardiopulmonary bypass and aortic cross-clamping increase the risk of cerebral embolization and cerebrovascular accident (CVA) to unacceptable levels [1]. Over the last 2 decades, a number of creative methods have been described for dealing with these high-risk patients. In patients with isolated coronary artery disease, off-pump coronary artery bypass, sometimes performed with alternative sites for proximal graft inflow, has been well described [4]. Proximal graft connectors have also eliminated the need for aortic manipulation [5]. Although the long-term patency of bypass grafts in this setting has yet to be determined, these operations can be performed with a significant reduction in the risk of cerebral damage. Patients requiring valve replacement, however, cannot be managed with these techniques. Therefore, multiple alternative methods, including apicoaortic conduit, endoaortic balloon or Foley catheter occlusion, and aortic valve replacement under profound hypothermic circulatory arrest (PHCA), have
Accepted for publication April 25, 2005. Address correspondence to Dr Girardi, Department of Cardiothoracic Surgery, Weill Medical College of Cornell University, 525 East 68th St, M-424, New York, NY 10021; e-mail: [email protected].
© 2005 by The Society of Thoracic Surgeons Published by Elsevier Inc
(Ann Thorac Surg 2005;80:1688 –92) © 2005 by The Society of Thoracic Surgeons
Material and Methods Between July 1997 and December 2004, 25 patients were referred for valve replacement or repair in the setting of a porcelain aorta. Their demographic data are listed in Table 1. At the time of their admission, a diagnosis of porcelain aorta was confirmed by the appearance of the aorta on admission chest radiograph or on fluoroscopy at the time of cardiac catheterization. All patients then had evaluation of their entire aorta with computed tomography scanning in order to evaluate possible sites for aortic reconstruction and cannulation in the ascending aorta and aortic arch. 0003-4975/05/$30.00 doi:10.1016/j.athoracsur.2005.04.044
GIRARDI ET AL VALVE SURGERY WITH PORCELAIN AORTA
Table 1. Preoperative Demographics for 25 Patients With a Porcelain Aorta Mean age (years) Range (years) Male : female Mean ejection fraction (%) NYHA class (n) I II III IV Hypertension (n) Previous MI (n) COPD (n) Previous CVA (n) Previous OHS (n)
74.5 54–89 14 : 11 42 0 4 10 11 24 12 13 5 5
COPD ⫽ chronic obstructive pulmonary disease; CVA ⫽ cerebrovascular accident; MI ⫽ myocardial infarction; NYHA ⫽ New York Heart Association; OHS ⫽ open heart surgery.
After standard anesthetic preparation, a median sternotomy was used to expose the ascending aorta, aortic arch, and the heart. The diagnosis of porcelain aorta was confirmed by gentle digital palpation of the aorta. Soft areas devoid of plaque were noted and marked as possible sites for aortic cannulation. The aorta was then examined by epiaortic echocardiography to determine the presence or absence of mobile atheroma in the proposed region of cannulation [2]. Patients with patchy calcification that was not circumferential or in whom a cross-clamp could be applied were excluded from this cohort. In 21 patients, the ascending aorta or arch were found to have small, isolated areas devoid of calcium. These locations were deemed suitable sites for aortic cannulation. Four additional patients were found to be without a suitable site for traditional cannulation and were placed on cardiopulmonary bypass through the femoral artery. Axillary cannulation was not found to be necessary in any patient. Heparin was administered at 400 mg/kg. Bicaval venous cannulation was utilized to facilitate the administration of retrograde cerebral perfusion (RCP) during PHCA [12]. Patients were then placed on cardiopulmonary bypass and core cooled to a bladder temperature of 18°C. While on bypass, mean arterial pressure was maintained between 70 and 80 mm Hg [13]. A right superior pulmonary vein vent was placed, and the ascending aorta was not clamped. Once the appropriate temperature was reached, 1 g pentothal was administered, and PHCA was initiated with the patient in a steep Trendelenberg position. The aorta was opened, and RCP was initiated at 150 to 300 cc/min, keeping the CVP less than 25 mm Hg. Retrograde cold, blood potassium cardioplegia was given during this initial phase of the operation after PHCA was begun. The aorta was then inspected and palpated, and a suitable area for reconstruction in the proximal arch was identified. If there was no obvious break in the circum-
1689
ferential calcification in this location, a local endarterectomy was performed. Aortic reconstruction was then performed with a one-branch Dacron prosthesis (Meadox Medical, Oakland, New Jersey) and 3-0 polypropylene suture. The suture line was then reinforced with horizontal mattress pledgetted sutures. In patients requiring endarterectomy, a neoadventitia was created with Teflon (Impra, subsidiary of L.R. Bard, Tempe, Arizona) felt strips outside this area. Cardiopulmonary bypass was then reinstituted through the side branch graft and systemic warming was initiated, maintaining a 10°C gradient between the blood and core temperature. Valve replacement, repair or coronary bypass grafting, or both, was then performed after this period of PHCA. The aortic reconstruction was then completed at the level of the sinotubular junction utilizing the aforementioned techniques. Aortic root replacement was not necessary in any of the 25 patients. During this phase of aortic reconstruction, myocardial protection was achieved by antegrade direct coronary ostial injection or retrograde coronary sinus delivery. All patients were given full Hammersmith dose aprotonin (6 million units), and blood product replacement was utilized as necessary. Postoperative hematocrit was maintained above 30%, and systolic blood pressure was optimized to 110 mm Hg or greater. All postoperative complications were recorded, as was in-hospital mortalTable 2. Intraoperative Data and Procedures for 25 Patients With a Porcelain Aorta Number of Patients (n ⫽ 25)
Primary Procedure Primary Procedure Aortic valve replacement Mitral valve replacement Mitral valve repair Additional procedures Ascending and hemiarch replacement Coronary artery bypass Aortic endarterectomy Tricuspid valve repair Reimplantation of SVGs Operative data Arterial cannulation Aortic Femoral Mean cooling time (minutes) Mean warming time (minutes) Mean PHCA time (minutes) Range Mean cardiac ischemic time (minutes) Range Mean cardiopulmonary bypass time (minutes) Range PHCA ⫽ profound hypothermic circulatory arrest; vein grafts.
22 2 1 25 15 4 1 1
21 4 32 82 19 14–29 96 59–159 170 117–312
SVG ⫽ saphenous
CARDIOVASCULAR
Ann Thorac Surg 2005;80:1688 –92
CARDIOVASCULAR
1690
GIRARDI ET AL VALVE SURGERY WITH PORCELAIN AORTA
Ann Thorac Surg 2005;80:1688 –92
Table 3. Postoperative Morbidity and Mortality Event Reexploration for bleeding Intra-aortic balloon pump/low cardiac output Cerebrovascular accident Perioperative myocardial infarction Permanent pacemaker Superficial sternal wound infection Intubation ⬎ 48 hours Tracheostomy Ischemic bowel Intraoperative death In-hospital death
Number of Patients (n ⫽ 25) 2 1 1 0 1 1 1 0 1 0 2
ity. This study was approved by the institutional review board of the Weill Medical College of Cornell University.
Statistical Analysis A retrospective, comparative statistical analysis of perioperative variables was performed using SPSS statistical package (SPSS, Chicago, Illinois). Univariate analysis was performed with 2 analysis. Statistical significance was defined by a p value of 0.05 or less.
Results A total of 25 patients with a porcelain aorta were referred for valvular heart surgery. A majority of the patients required aortic valve replacement as their primary procedure (n ⫽ 22), whereas the remainder were referred with mitral valve disease (n ⫽ 3). The preoperative demographics for this cohort are listed in Table 1. A majority of the patients required procedures in addition to their primary valve procedure (Table 2). Sixty percent of patients required coronary revascularization, and 16% required an aortic endarterectomy to safely reconstruct the aorta in the arch or at the sinotubular junction, or both. One patient with a previous CABG required reimplantation of a patent saphenous vein graft. The other 4 with patent internal mammary artery grafts had this graft identified and controlled during the procedure to enhance myocardial protection. The patient undergoing mitral valve repair also had significant tricuspid regurgitation, and a valvuloplasty was necessary. Table 2 also demonstrates the operative details of these procedures. The majority of patients reached a core temperature of approximately 18°C by 30 minutes of systemic cooling (mean cooling time, 32 minutes). The greater range in times of systemic warming are due to the varying number of additional procedures required. No patient required a period of PHCA longer than 29 minutes. Three patients were on bypass for longer than 200 minutes, 1 requiring 312 minutes of extracorporeal circulation. Postoperative complications and mortality are highlighted in Table 3. Although 20% of patients had previous
CABG surgery and 60% of patients required additional bypass grafting, no patient had a documented myocardial infarction. In addition, despite the advanced age of the patients, none had respiratory failure requiring tracheostomy. One patient had a nonfatal CVA (left-sided weakness) and recovered full function before discharge. No patient required hemodialysis. Univariate risk factors for death following these operations are listed in Table 4. There were no intraoperative deaths. One of the 2 postoperative deaths (8%) occurred in a 79-year-old man with critical aortic stenosis, severe aortic insufficiency, a previous CABG, and an ejection fraction of 30%. He had low cardiac output after his extensive procedure (CPB time, 312 minutes) that included an aortic endarterectomy and reimplantation of patent saphenous vein grafts. He also required reexploration for postoperative hemorrhage. He subsequently died on postoperative day 6. The other death occurred in an 82-year-old woman with critical aortic stenosis, moderate aortic insufficiency, and ejection fraction of 40%. She also required two bypass grafts. Ischemic bowel developed on postoperative day 4, and she was taken for exploratory laparotomy. The entire colon and small intestine was gangrenous, and the patient was taken back to the intensive care unit and allowed to die without aggressive efforts.
Comment Patients with severe atherosclerotic disease of the aorta are at particularly high risk for stroke and death after cardiac surgery. In a review of 221 patients having cardiac procedures on cardiopulmonary bypass, Blauth and coworkers [14] found that 22% had atheroemboli, a majority being embolic events to the cerebral circulation. In patients with severe aortic atherosclerosis, the risk was greatest with 37% experiencing an embolic event. Gillinov and colleagues [15] reported their experience with a similar patient population undergoing aortic valve replacement. Utilizing a number of operative strategies to minimize the risk of cerebral embolization, they reduced the incidence of CVA in this group to 10% with a hospital mortality of 14%. Eighteen percent (n ⫽ 11) of this cohort of 62 patients had a “porcelain aorta.” This highest risk subset was also treated with a variety of methods. They, however, had a marked increase in stroke and mortality
Table 4. Univariate Risk Factors for Death After Aortic Replacement for Patients With a Porcelain Aorta p Value Preoperative variable Age ⬎ 78 years Intraoperative/postoperative variable Cardiopulmonary bypass time ⬎ 200 minutes Reexploration for hemorrhage Gastrointestinal complication Need for intra-aortic balloon pump
0.009 0.0001 0.02 0.001 0.001
(3 of 11, 27%) compared with the other patients in this series. Of the various techniques utilized, this report, like others before [2, 16], found aortic replacement under circulatory arrest to provide the least risk of cerebral injury. Patients being treated with this technique based on minimizing aortic manipulation and utilizing a short period of PHCA (mean time, 17 minutes) were spared cerebral injury. While some have been unable to duplicate the above results utilizing PHCA [17], we have embraced this approach in all our patients with significant valvular heart disease and a porcelain aorta, and believe this technique provides the cardiac surgeon with the best opportunity to treat the underlying cardiac pathology while minimizing the potential for a devastating cerebrovascular accident. Because nearly 2% of all cardiac surgery patients have severe aortic atherosclerosis [1], and approximately one fifth of this group will have the extreme “porcelain” subtype, strategies to safely manage this population are needed. Patients with a severely calcified ascending aorta who require isolated CABG may be treated with innovative methods aimed at reducing atheroemboli during the procedure. Off-pump coronary artery bypass graft surgery (OPCABG) is a safe strategy that can be performed without aortic cross-clamping and the potential for atheroembolism generated by the heart and lung machine. Alternative sites for proximal anastomoses can completely eliminate aortic manipulation and may further reduce the incidence of stroke. The evolution of proximal connector devices may offer additional benefits for patients with severely atherosclerotic aortas requiring bypass surgery [4, 5]. Patients with advanced valvular heart disease will require cardiopulmonary bypass for valve replacement or repair. In patients with a porcelain aorta and mitral insufficiency or stenosis, surgery can be safely performed without aortic cross-clamping. Recent advancements in minimally invasive mitral valve surgery have led to the development of alternative strategies for arterial cannulation, endoaortic balloon occlusion, and retrograde cardioplegia [18]. In patients without significant aortic insufficiency, hypothermic fibrillation on cardiopulmonary bypass can also provide adequate myocardial protection and valve exposure for patients not requiring concomitant coronary artery bypass [19]. Although successful outcomes utilizing either of these strategies have been reported, it may be difficult to duplicate the usually low morbidity and mortality rates with these techniques in the elderly population with a porcelain aorta. These patients often have severe atherosclerosis of the descending aorta and peripheral vasculature that can make alternative sites for arterial cannulation and endoaortic manipulation less desirable and significantly more technically challenging. Axillary artery cannulation may offer some advantages in this setting [20]. Although only 3 patients in our report had mitral valve disease as their primary cardiac pathology, we believe aortic replacement under PHCA can be safely performed with similarly good outcomes. An overwhelming majority of patients can be managed with central aortic cannulation and antegrade
GIRARDI ET AL VALVE SURGERY WITH PORCELAIN AORTA
1691
cardiopulmonary bypass, thus eliminating the possibility of retrograde embolization of debris from the descending thoracic aorta. It also reduces the incidence of retrograde aortic dissection and balloon migration that has been reported utilizing endoaortic techniques. In patients with a porcelain aorta needing mitral valve surgery, a complete evaluation of their arterial system is appropriate. That will provide the surgeon with the information necessary to choose the surgical approach they are most comfortable with for these high-risk patients. Patients in need of aortic valve replacement in the setting of a porcelain aorta are often turned down for surgery because the risk of stroke is thought to be prohibitive. However, the natural history of medically treated severe aortic valve disease, particularly aortic stenosis, is dismal. In a series of 100 symptomatic patients with critical aortic stenosis treated with medical therapy alone, there was a 33% mortality in the first year after the development of symptoms [21]. Over the last 2 decades, a number of innovative techniques have been described that have the common pathway of minimizing manipulation of the severely calcified aorta while performing aortic valve replacement under PHCA or with aortic endarterectomy. Aortic valve replacement under PHCA was first described in 1986. In 2 cases, the aortic valve was replaced during 38 and 44 minutes of circulatory arrest without neurologic injury or death [7]. A similar approach was espoused by Bryne and colleagues [22] in a 1998 report on 3 patients undergoing the same procedure. Despite a mean PHCA period of 54 minutes, the results were again excellent. Aortic endarterectomy is also useful in this setting. Svensson and colleagues [23] described 6 cases of extensive ascending aortic endarterectomy in patients requiring aortic replacement. Only 1 patient sustained a neurologic deficit, and there were no deaths. However, in the patients with a truly porcelain aorta, PHCA was still required, thus eliminating the potential advantages of this simpler technique. In addition, follow-up was quite limited, and the potential for aneurysmal degeneration of the endarterectomized aorta remains unknown. Kouchoukos’s group [2] was the first to describe aortic replacement under PHCA for patients with a porcelain aorta. Of 540 patients undergoing cardiac surgery, 10 had severe diffuse atheromatous disease and were treated with graft replacement of the ascending aorta under PHCA. The mortality rate for this procedure was 10%. There were no strokes, but 1 of the 10 patients had a transient neurologic deficit that resolved before discharge. These results were more remarkable when considering that all these patients were perfused through the femoral artery and that 3 had severe enough carotid disease to mandate concomitant endarterectomy. A follow-up report confirmed the efficacy of this approach in a larger cohort of patients [16]. A recent report in 44 patients having aortic replacement in this clinical setting revealed a stroke risk of 11% with an operative mortality of 6.8% [24]. Certainly, conclusions from any nonrandomized, retrospective analysis of a small cohort of patients should be interpreted with caution. However, we believe the results
CARDIOVASCULAR
Ann Thorac Surg 2005;80:1688 –92
CARDIOVASCULAR
1692
GIRARDI ET AL VALVE SURGERY WITH PORCELAIN AORTA
with aortic replacement under PHCA reaffirm this technique’s utility in minimizing neurologic injury. Twenty percent of our patients had previous strokes yet only 1 had a focal neurologic deficit after surgery. With replacement of the diseased aorta, there is no risk of aneurysm formation after surgery, and the risk of embolization from a calcified and diseased ascending aorta and proximal arch is eliminated. The operative mortality from this procedure, 8%, is similar to that of others performing this procedure [2, 16, 24] and correlates strongly with the need for extensive procedures and prolonged periods of cardiopulmonary bypass. Perhaps a less invasive approach dealing only with the patient’s valve disease will prove to be more efficacious for elderly patients who may not tolerate extreme intervention [25].
References 1. Mills NL, Everson CT. Atherosclerosis of the ascending aorta and coronary artery bypass. J Thorac Cardiovasc Surg 1991; 102:546 –53. 2. Wareing TH, Davila-Roman VG, Barzilai B, et al. Management of the severely atherosclerotic ascending aorta during cardiac operations. J Thorac Cardiovasc Surg 1992;103:453– 62. 3. Tobler HG, Edwards JE. Frequency and location of atherosclerotic plaques in the ascending aorta. J Thorac Cardiovasc Surg 1988;96:304 – 6. 4. Sabik JF, Gillinov AM, Blackstone EH, et al. Does off-pump coronary surgery reduce morbidity and mortality? J Thorac Cardiovasc Surg 2002;124:698 –707. 5. Gunnert JF, Bossert T, Mohr FW. The use of an aortic connector system in a patient with severely calcified ascending aorta. J Card Surg 2004;19:62– 4. 6. Cosgrove DM. Management of the calcified aorta: an alternative method of occlusion. Ann Thorac Surg 1983;36:718 –9. 7. Coselli JS, Crawford ES. Aortic valve replacement in the patient with extensive calcification of the ascending aorta (the porcelain aorta). J Thorac Cardiovasc Surg 1986;91: 184 –7. 8. Culliford AT, Colvin SB, Rohrer K, et al. The atherosclerotic ascending aorta and transverse arch. A new technique to prevent cerebral injury during bypass: experience with 13 patients. Ann Thorac Surg 1986;41:27–35. 9. Black JJM, Allan A, Williams BT. The use of foley balloon catheters in cardiac surgery. Eur J Cardiothorac Surg 1993; 7:617–9. 10. Liddicoat JR, Doty JR, Stuart RS. Management of the atherosclerotic ascending aorta with endoaortic occlusion. Ann Thorac Surg 1998;65:1133–5.
Ann Thorac Surg 2005;80:1688 –92
11. Skrabal CA, Loebe M, Thompson LO, et al. Apicoaortic conduit in a patient with severe hemolysis after three aortic valve replacements. J Thorac Cardiovasc Surg 2004;127: 270 –2. 12. Coselli JS. Retrograde cerebral perfusion via a superior vena caval cannula for aortic arch aneurysm operations. Ann Thorac Surg 1994;57:1668 –9. 13. Gold JP, Charlson ME, Williams-Russo P, et al. Improvement of outcomes after coronary artery bypass: a randomized trial comparing intraoperative high versus low mean arterial pressure. J Thorac Cardiovasc Surg 1995;110:1302–14. 14. Blauth CI, Cosgrove DM, Webb BW, et al. Atheroembolism from the ascending aorta: an emerging problem in cardiac surgery. J Thorac Cardiovasc Surg 1992;103:1104 –12. 15. Gillinov AM, Lytle BW, Hoang V, et al. The atherosclerotic aorta at aortic valve replacement: surgical strategies and results. J Thorac Cardiovasc Surg 2000;120:957– 65. 16. Kouchoukos NT, Wareing TH, Daily BB, et al. Management of the severely atherosclerotic aorta during cardiac operations. J Card Surg 1994;9:490 – 4. 17. King RC, Kanithanon RC, Shockey KS, et al. Replacing the atherosclerotic ascending aorta is a high-risk procedure. Ann Thorac Surg 1998;66:396 – 401. 18. Reichenspurner H, Detter C, Deuse T, et al. Video and robotic-assisted minimally invasive mitral valve surgery: a comparison of the port-access and transthoracic clamp techniques. Ann Thorac Surg 2005;79:485–91. 19. Calleja F, Martinez JL, Gonzales De Vega N. Mitral valve surgery through a right thoracotomy. J Cardiovasc Surg 1996;37(Suppl 1):49 –52. 20. Baribeau RY, Westbrook BM, Charlesworth DC, et al. Arterial inflow via an axillary artery graft for the severely atheromatous aorta. Ann Thorac Surg 1998;66:33–7. 21. Rosenhek R, Binder T, Porenta G, et al. Predictors of outcome in severe asymptomatic aortic stenosis. N Engl J Med 2000;343:611–7. 22. Byrne JG, Aranki SF, Cohn LH. Aortic valve operations under deep hypothermic circulatory arrest for the porcelain aorta: “no-touch” technique. Ann Thorac Surg 1998:65: 1313–5. 23. Svensson LG, Sun J, Cruz HA, et al. Endarterectomy for calcified porcelain aorta associated with aortic valve stenosis. Ann Thorac Surg 1996;61:149 –52. 24. Aranki SF, Nathan M, Shekar P, et al. Hypothermic circulatory arrest enable aortic valve replacement in patients with unclampable aorta. Society of Thoracic Surgery, Plenary Session, Tampa, Florida, January 2005. 25. Lutter G, Ardehali R, Cremer J, et al. Percutaneous valve replacement: current state and future prospects. Ann Thorac Surg 2004;78:2199 –206.