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Comparison of simultaneous Doppler- and catheter-derived right ventricular dPdt in hypoplastic left heart syndrome
Comparison of Simultaneous Dopplerand Catheter-derived Ri ht Ventricular dP/dt in Hypoplastic Le 3t Heart Syndrame Erik C. Michelfelder, Robert
MD, Roger H. Beekman,
P. Vermilion, MD, Achiahu Ludomirsky, MD, and Thomas R. Lloyd, MD
0
uantification of right ventricular (RV) function in children undergoing staged, univentricular repair of hypoplastic left heart syndrome is of importance both in guiding surgical palliation and in following RV performance. Estimation of RV function based on \/olume analysis is difficult because of the complexity of RV geometry. The first derivative of ventricular pressure rise (dP/dt), measured by cardiac catheterization using highlidelity? micromanometer-tipped catheters, is a useful index in quantifying ventricular systolic function. Recently. estimates of dP/dt have been calculated by continuous-wave Doppler echocardiography using velocities derived from atrioventricular valve regurgitant jets. Doppler assessment of left ventricular dP/dt has been shown to correlate with catheter-derived values in both animal’ studies and human adults.2A RV dP/dt has also been estimated by continuous-wave Doppler, and shown to correlate with catheter-derived dP/dt? however, these studies calculated dP/dt in low-pressure right \/entricles. No studies have validated Doppler estimation of RV dP/dt in systemic-pressure right ventricles, a physiologic circumstance common in children with complex congenital heart disease. This study examines whether estimation of RV dP/dt using continuous-wave Doppler correlates with simultaneous catheter-derived RV dP/dt in children with hypoplastic left heart syndrome, a population in which the right ventricle supports systemic circulation. . . . This study was undertaken after approval by the institutional review board 1920 -of the University of Michigan Medical Center. Thirteen consecutive patients (9 boys and 4 girls) undergoing cardiac catheterization in the course of staged surgical palliation of hypoplastic left heart syndrome, with sufficient tricuspid regurgitation for Doppler analysis, were studied. The diagnosis of hypoplastic left heart syndrome was limited to patients with hypoplastic left ventricles associated with mitral and/or aortic atresia or hypoplasia. Patients with unbalanced atrioventricular From the Division of Pediatric Carciolog\;, C.S. Mott Children’s kspital. University ol Michigx Medical Center. knn krjor Michipn. D?. Verrniliop’s add:ess is: Ur;krsih/ 01 Mic?liyan ,Mcdical Center. 1 X0 East McdicoI Cmtel Drive, MCilC F i 3 10, Box 0204, 4nr Arbor, Michigari 48 109. Manuscr ipl received JLns 29, 1905 : revised menuscript rcceibed and acc-?pted September 19, 1995.
212
THE LvXERICAN
JOURNAL
OF CARLIOIOGY’
septal defects or more complex single ventricular anatomy were excluded. Four patients were status-post Norwood 1 palliation. 2 patients were status-post bidirectional Glenn or hemi-Fontan procedures, and 7 patients were status-post fenestrated Fontan procedure. Patient weight ranged f?om 3.6 to 18.0 kg (mean IO. 1). Patients underwent catheterization using standard techniques. Sedation was achieved during cathcterization with either midazolam and morphine sulfate, ketamine, or demerol with hydroxyzine. In 7 patients who underwent catheterization after the fenestrated Fontan procedure, general endotracheal anesthesia was used to allow closure of tbc fenestration in the catheterization laboratory. A 2Fr micromanometer catheter (Millar Instruments, Houston, Texas) was advanced through a pigtail catheter passed retrograde into the right ventricle6 in 12 patients; in 1 patient, the Millar catheter was advanced into the right ventricle through an end-hole catheter placed anterograde across the tricuspid valve. The RV pressure trace was electronically differentiated and recorded on paper over multiple cardiac cycles (Figure 1) simultaneously with acquisition of Doppler data.
----I--
1 set ----4--100
FIGURE 1. Right ventricular first derivative of tracing (thick arrow] recorded simultaneously tracing and electrocardiogram. Open arrow marker used to identify same cardiac cycles
i/O-.
77
MD,
]ANUhRY
15,
I936
ventricular pressure rise (dp/dt] with right ventricular pressure indicates electrocardiographic on catheter and Doppler tracings.
Doppler examination was performed using steerable continuous-wave Doppler with 2 to 5 MHz transducers (Acuson. Mountain View, California). Parastemal short-axis or apical 4chamber views were used to obtain images. Optimal alignment with the tricuspid regurgitant jet was confirmed by color flow Doppler imaging. Doppler traces were recorded onto a strip chart with an electrocardiographic recording (Figure 2); electrocardiographic markers allowed synchronization of Doppler and catheter recordings. Calculation of Doppler-derived RV dP/dt was performed off-line by 2 independent observers. With use of the simplified Bernoulli equation, RV dP/dt was calculated between flow velocitics of 0 to 2 and 1 to 3 m/s as the pressure change (in mm Hg) per unit of time (seconds). FIGURE Doppler- and catheter-derived peak RV dP/dt occurring values were calculated as the average of the change same 3 cardiac cycles. Doppler and catheter data were rccordcd on separate traces to allow blinded measurement of peak RV dP/dt values by each method. Simple linear regression was used to compare Doppler-derived RV dP/dt values, calculated between 0 to 2 and I to 3 m/s, with values measured by a micromanometer-tipped catheter for the same heartbeats. Interobserver variability was assessed by determination of the correlation coelficicnt, r*, as well as by determining interobserver difference. Peak RV dP/dt measured by micromanometcr catheter ranged from 564 to 1,716.S. mm Hg/s. The mean Doppler RV dP/dt calculated between 1 and 3 and 0 and 2 m/s ranged from 516 to 1,505 and from 397 to I, 193.5 mm Hg/s, respectively. Regression analysis indicated that Doppler-derived RV dP/dr calculated between 1 and 3 m/s correlated well with catheter measurements (r* = 0.79, p
p
2. Doppler recording of tricuspid regurgitant iet ~tfricker orrows~ during the same cardiac cycle identified in Figure 1. AP = in pressure; At = change in time.
derived RV dP/dt calculated between 0 and 2 m/s showed only fair correlation (r2 = 0.57) with catheter-derived values (Figure 4). The mean difference between RV dP/dt calculated by Doppler between I and 3 m/s and by catheter was -175 f 40 mm Hg/s. Interobserver variability for Doppler-derived dP/dt calculated between 1 and 3 m/s was small (r2 = 0.88. mean interobserver difference 9.4%); interobserver variability for values calculated between 0 and 2 m/s was significant (3 = 0.46, mean interobserver difference 23.3%). . . . This study indicates that Doppler-derived RV dP/dt corresponds well to catheter-derived peak dP/dt values in children with hypoplastic left heart syndrome. It is the first study to validate Doppler-derived RV dP/dt in a condition where the right ventricle is the systemic ventricle. Determination of RV dP/dt from Doppler tracings of the tricuspid valve regurgitant jet between 1 and 3 m/s cor-
1,200.
E 0
$
SOOi
k E
I
300
600
900
Catheter
RV peak dP/dt
1,200
1,500
1,800
HGURE 3. Comparison of right ventricular first derivative of ventricular pressure rise (RV dP/dt) values derived by Doppler analysis of tricuspid regur ilunt $t velocities between 1 and 3 catheter. m/s, with values measu re! by micromanometer-tipped
Catheter
RV peak dP/dt
FIGURE 4. Comparison of right ventricukr first derivative of ventricular pressure rise (RV dP/dt) values detived by Doppler analysis of tricuspid regur itant +t vetocities between 0 and 2 m/s, with values measu re! by micromanometer-tipped catheter.
BRIEF RCKXrS
213
related well with catheter-derived values. In addition, values calculated between I and 3 m/s showed good reproducibility between observers. Detcrmindtion of dP/dt from tracings between 0 and 2 m/s correlated less well. and were not adequately reproducible. Accurate determination ol’ the point of intersection of the Doppler envelope with the baseline (0 m/s flow velocity) was difficult. Atrioventricular valve closure “noise,” as well as baseline artifact, often obscured the point of separation of the Doppler envelope from the baseline. and made accurate determination of this point diflicult. Previous studies have validated RV dP/dt IYom Doppler-estimated pressure changes occurring at lower flow velocities, generally at velocity intervals occurring at 12 m/s.j Tn these studies, however, RV dP/dt was estimated in lower pressure, nonsystemic right ventricles, where peak flow velocity may never reach 3 m/s, and the peak rate of prcssurc change therelore occurs at lower overall prcssurcs. Our results indicate that estimating RV dP/dt between 0 and 2 m/s in a systemic right ventricle is relatively inaccurate and difficult to reproduce. Our findings in systemic-pressure right ventricles concur more closely with previous studies validating left ventricular dP/dt,‘-’ where Doppler values estimated from pressure changes occurring between I and 3 m/s have correlated best with catheter measurements. Doppler measurements consistently underestimate micromanometer catheter measurement of peak RV dP/dt (Figure 3). This is explained, in part, by the method used with the Doppler technique. Estimation of dP/dt from Doppler assumes that averaging the change in pressure that occurs between 2 points in time during ventricular systole will approximate the peak instantaneous pressure rise. By averaging 2 moments in time that may approx-
Aortic
imate, but never exceed, peak dP/dt, Doppler estimation of peak dP/dt will always be less than or equal to the true peak dP/dt. Validation of Doppler RV dP/dt as a method of estimating RV systolic function has potential utility not only in hypoplastic left heart syndrome, but also in a variety of other anatomic defects. including unbalanced atrioventricular septal defect, atrially repaired d-transposition of the great arteries, and in complex single ventticular anatomy. Estimation of dP/dt can be readily performed on-line on many echocardiographic systems using available software. Doppler estimation of RV dP/dt correlates well with micromanometer catheter-measured values in children with hypoplastic left heart syndrome. Doppler estimation of RV dP/dt is a method of quantifying RV systolic function independent of geometric assumptions, and may be a valuable method for longitudinal analysis of RV function.
Dissection With Flap’ Prolapse into the Left Ventricle
Barry P. Rosenzweig, MD, Steven Goldstein, MD, Mark Sherrid, MD, and ltzhak Kronzon, MD scending thoracic aortic dissection (AD) is often a A catastrophic condition. Aonic regurgitation (AR) is a common complication requiring immediate recognition for prompt. sometimes life-saving surgery. AR due to AD has been ascribed to commissural dehiscence or aortic root deformation.‘.” We describe 6 patients with an unusual complication of dissection, namely intimal ilap prolapse through the aortic valve into the left ventricle. . . . Table 1 lists the clinical and diagnostic findings of these 6 patients. They comprise <20/Cof all patients with AD diagnosed by echocardiography at our institution. From tclc Cepartments oi h’\edicin, = of New “ark IJniversibq ,b/\edical Cen’er and Roosevelt Hosvitul, NW\) York. NW/ York, ard ihe Washing-w Hosp?ul Center, V(/clsliington C.C. Cr. Krowon s address is: 560 First Avenue. New York. I\!ew York 130!6. ManuscriDt received +:I 18, 1995. rev:scd mnancscri:)t received and accepted October 2. 199.5.
Four patients had a history of hypertension; 5 presented first with sudden onset of chest pain. This progressed to back pain in 1 patient and abdominal and back pain in another. In 1 patient, chest pain was associated with syncope. Another patient collapsed suddenly and was brought unconscious to the emergency room. Two patients had hypotension and 2 others had wide pulse pressures. A precordial diastolic murmur suggestive of AR was heard in only 2 patients. One patient (no. I) without a diastolic murmur had a mid-diastolic click, and had hemiplegia on admission. One patient (no. 5) had evidence of aortic occlusion with no palpable pulses in any artery originating beyond the left carotid artery and paraplegia. This patient also had signs of congestive heart Failure. Contrast computed tomography of the chest was performed in 4 patients, and showed AD in 3. Tn the fourth patient, AD was not seen. Circumferential tear or intima1prolapse into the left ventricle as well as AR could JAWAR”
: 5,
1996
MD, Roger H. Beekman,
P. Vermilion, MD, Achiahu Ludomirsky, MD, and Thomas R. Lloyd, MD
0
uantification of right ventricular (RV) function in children undergoing staged, univentricular repair of hypoplastic left heart syndrome is of importance both in guiding surgical palliation and in following RV performance. Estimation of RV function based on \/olume analysis is difficult because of the complexity of RV geometry. The first derivative of ventricular pressure rise (dP/dt), measured by cardiac catheterization using highlidelity? micromanometer-tipped catheters, is a useful index in quantifying ventricular systolic function. Recently. estimates of dP/dt have been calculated by continuous-wave Doppler echocardiography using velocities derived from atrioventricular valve regurgitant jets. Doppler assessment of left ventricular dP/dt has been shown to correlate with catheter-derived values in both animal’ studies and human adults.2A RV dP/dt has also been estimated by continuous-wave Doppler, and shown to correlate with catheter-derived dP/dt? however, these studies calculated dP/dt in low-pressure right \/entricles. No studies have validated Doppler estimation of RV dP/dt in systemic-pressure right ventricles, a physiologic circumstance common in children with complex congenital heart disease. This study examines whether estimation of RV dP/dt using continuous-wave Doppler correlates with simultaneous catheter-derived RV dP/dt in children with hypoplastic left heart syndrome, a population in which the right ventricle supports systemic circulation. . . . This study was undertaken after approval by the institutional review board 1920 -of the University of Michigan Medical Center. Thirteen consecutive patients (9 boys and 4 girls) undergoing cardiac catheterization in the course of staged surgical palliation of hypoplastic left heart syndrome, with sufficient tricuspid regurgitation for Doppler analysis, were studied. The diagnosis of hypoplastic left heart syndrome was limited to patients with hypoplastic left ventricles associated with mitral and/or aortic atresia or hypoplasia. Patients with unbalanced atrioventricular From the Division of Pediatric Carciolog\;, C.S. Mott Children’s kspital. University ol Michigx Medical Center. knn krjor Michipn. D?. Verrniliop’s add:ess is: Ur;krsih/ 01 Mic?liyan ,Mcdical Center. 1 X0 East McdicoI Cmtel Drive, MCilC F i 3 10, Box 0204, 4nr Arbor, Michigari 48 109. Manuscr ipl received JLns 29, 1905 : revised menuscript rcceibed and acc-?pted September 19, 1995.
212
THE LvXERICAN
JOURNAL
OF CARLIOIOGY’
septal defects or more complex single ventricular anatomy were excluded. Four patients were status-post Norwood 1 palliation. 2 patients were status-post bidirectional Glenn or hemi-Fontan procedures, and 7 patients were status-post fenestrated Fontan procedure. Patient weight ranged f?om 3.6 to 18.0 kg (mean IO. 1). Patients underwent catheterization using standard techniques. Sedation was achieved during cathcterization with either midazolam and morphine sulfate, ketamine, or demerol with hydroxyzine. In 7 patients who underwent catheterization after the fenestrated Fontan procedure, general endotracheal anesthesia was used to allow closure of tbc fenestration in the catheterization laboratory. A 2Fr micromanometer catheter (Millar Instruments, Houston, Texas) was advanced through a pigtail catheter passed retrograde into the right ventricle6 in 12 patients; in 1 patient, the Millar catheter was advanced into the right ventricle through an end-hole catheter placed anterograde across the tricuspid valve. The RV pressure trace was electronically differentiated and recorded on paper over multiple cardiac cycles (Figure 1) simultaneously with acquisition of Doppler data.
----I--
1 set ----4--100
FIGURE 1. Right ventricular first derivative of tracing (thick arrow] recorded simultaneously tracing and electrocardiogram. Open arrow marker used to identify same cardiac cycles
i/O-.
77
MD,
]ANUhRY
15,
I936
ventricular pressure rise (dp/dt] with right ventricular pressure indicates electrocardiographic on catheter and Doppler tracings.
Doppler examination was performed using steerable continuous-wave Doppler with 2 to 5 MHz transducers (Acuson. Mountain View, California). Parastemal short-axis or apical 4chamber views were used to obtain images. Optimal alignment with the tricuspid regurgitant jet was confirmed by color flow Doppler imaging. Doppler traces were recorded onto a strip chart with an electrocardiographic recording (Figure 2); electrocardiographic markers allowed synchronization of Doppler and catheter recordings. Calculation of Doppler-derived RV dP/dt was performed off-line by 2 independent observers. With use of the simplified Bernoulli equation, RV dP/dt was calculated between flow velocitics of 0 to 2 and 1 to 3 m/s as the pressure change (in mm Hg) per unit of time (seconds). FIGURE Doppler- and catheter-derived peak RV dP/dt occurring values were calculated as the average of the change same 3 cardiac cycles. Doppler and catheter data were rccordcd on separate traces to allow blinded measurement of peak RV dP/dt values by each method. Simple linear regression was used to compare Doppler-derived RV dP/dt values, calculated between 0 to 2 and I to 3 m/s, with values measured by a micromanometer-tipped catheter for the same heartbeats. Interobserver variability was assessed by determination of the correlation coelficicnt, r*, as well as by determining interobserver difference. Peak RV dP/dt measured by micromanometcr catheter ranged from 564 to 1,716.S. mm Hg/s. The mean Doppler RV dP/dt calculated between 1 and 3 and 0 and 2 m/s ranged from 516 to 1,505 and from 397 to I, 193.5 mm Hg/s, respectively. Regression analysis indicated that Doppler-derived RV dP/dr calculated between 1 and 3 m/s correlated well with catheter measurements (r* = 0.79, p
p
2. Doppler recording of tricuspid regurgitant iet ~tfricker orrows~ during the same cardiac cycle identified in Figure 1. AP = in pressure; At = change in time.
derived RV dP/dt calculated between 0 and 2 m/s showed only fair correlation (r2 = 0.57) with catheter-derived values (Figure 4). The mean difference between RV dP/dt calculated by Doppler between I and 3 m/s and by catheter was -175 f 40 mm Hg/s. Interobserver variability for Doppler-derived dP/dt calculated between 1 and 3 m/s was small (r2 = 0.88. mean interobserver difference 9.4%); interobserver variability for values calculated between 0 and 2 m/s was significant (3 = 0.46, mean interobserver difference 23.3%). . . . This study indicates that Doppler-derived RV dP/dt corresponds well to catheter-derived peak dP/dt values in children with hypoplastic left heart syndrome. It is the first study to validate Doppler-derived RV dP/dt in a condition where the right ventricle is the systemic ventricle. Determination of RV dP/dt from Doppler tracings of the tricuspid valve regurgitant jet between 1 and 3 m/s cor-
1,200.
E 0
$
SOOi
k E
I
300
600
900
Catheter
RV peak dP/dt
1,200
1,500
1,800
HGURE 3. Comparison of right ventricular first derivative of ventricular pressure rise (RV dP/dt) values derived by Doppler analysis of tricuspid regur ilunt $t velocities between 1 and 3 catheter. m/s, with values measu re! by micromanometer-tipped
Catheter
RV peak dP/dt
FIGURE 4. Comparison of right ventricukr first derivative of ventricular pressure rise (RV dP/dt) values detived by Doppler analysis of tricuspid regur itant +t vetocities between 0 and 2 m/s, with values measu re! by micromanometer-tipped catheter.
BRIEF RCKXrS
213
related well with catheter-derived values. In addition, values calculated between I and 3 m/s showed good reproducibility between observers. Detcrmindtion of dP/dt from tracings between 0 and 2 m/s correlated less well. and were not adequately reproducible. Accurate determination ol’ the point of intersection of the Doppler envelope with the baseline (0 m/s flow velocity) was difficult. Atrioventricular valve closure “noise,” as well as baseline artifact, often obscured the point of separation of the Doppler envelope from the baseline. and made accurate determination of this point diflicult. Previous studies have validated RV dP/dt IYom Doppler-estimated pressure changes occurring at lower flow velocities, generally at velocity intervals occurring at 12 m/s.j Tn these studies, however, RV dP/dt was estimated in lower pressure, nonsystemic right ventricles, where peak flow velocity may never reach 3 m/s, and the peak rate of prcssurc change therelore occurs at lower overall prcssurcs. Our results indicate that estimating RV dP/dt between 0 and 2 m/s in a systemic right ventricle is relatively inaccurate and difficult to reproduce. Our findings in systemic-pressure right ventricles concur more closely with previous studies validating left ventricular dP/dt,‘-’ where Doppler values estimated from pressure changes occurring between I and 3 m/s have correlated best with catheter measurements. Doppler measurements consistently underestimate micromanometer catheter measurement of peak RV dP/dt (Figure 3). This is explained, in part, by the method used with the Doppler technique. Estimation of dP/dt from Doppler assumes that averaging the change in pressure that occurs between 2 points in time during ventricular systole will approximate the peak instantaneous pressure rise. By averaging 2 moments in time that may approx-
Aortic
imate, but never exceed, peak dP/dt, Doppler estimation of peak dP/dt will always be less than or equal to the true peak dP/dt. Validation of Doppler RV dP/dt as a method of estimating RV systolic function has potential utility not only in hypoplastic left heart syndrome, but also in a variety of other anatomic defects. including unbalanced atrioventricular septal defect, atrially repaired d-transposition of the great arteries, and in complex single ventticular anatomy. Estimation of dP/dt can be readily performed on-line on many echocardiographic systems using available software. Doppler estimation of RV dP/dt correlates well with micromanometer catheter-measured values in children with hypoplastic left heart syndrome. Doppler estimation of RV dP/dt is a method of quantifying RV systolic function independent of geometric assumptions, and may be a valuable method for longitudinal analysis of RV function.
Dissection With Flap’ Prolapse into the Left Ventricle
Barry P. Rosenzweig, MD, Steven Goldstein, MD, Mark Sherrid, MD, and ltzhak Kronzon, MD scending thoracic aortic dissection (AD) is often a A catastrophic condition. Aonic regurgitation (AR) is a common complication requiring immediate recognition for prompt. sometimes life-saving surgery. AR due to AD has been ascribed to commissural dehiscence or aortic root deformation.‘.” We describe 6 patients with an unusual complication of dissection, namely intimal ilap prolapse through the aortic valve into the left ventricle. . . . Table 1 lists the clinical and diagnostic findings of these 6 patients. They comprise <20/Cof all patients with AD diagnosed by echocardiography at our institution. From tclc Cepartments oi h’\edicin, = of New “ark IJniversibq ,b/\edical Cen’er and Roosevelt Hosvitul, NW\) York. NW/ York, ard ihe Washing-w Hosp?ul Center, V(/clsliington C.C. Cr. Krowon s address is: 560 First Avenue. New York. I\!ew York 130!6. ManuscriDt received +:I 18, 1995. rev:scd mnancscri:)t received and accepted October 2. 199.5.
Four patients had a history of hypertension; 5 presented first with sudden onset of chest pain. This progressed to back pain in 1 patient and abdominal and back pain in another. In 1 patient, chest pain was associated with syncope. Another patient collapsed suddenly and was brought unconscious to the emergency room. Two patients had hypotension and 2 others had wide pulse pressures. A precordial diastolic murmur suggestive of AR was heard in only 2 patients. One patient (no. I) without a diastolic murmur had a mid-diastolic click, and had hemiplegia on admission. One patient (no. 5) had evidence of aortic occlusion with no palpable pulses in any artery originating beyond the left carotid artery and paraplegia. This patient also had signs of congestive heart Failure. Contrast computed tomography of the chest was performed in 4 patients, and showed AD in 3. Tn the fourth patient, AD was not seen. Circumferential tear or intima1prolapse into the left ventricle as well as AR could JAWAR”
: 5,
1996