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The B-bump: A Marker for Elevated Left Ventricular End-Diastolic Pressure
TECHNOLOGY SERIES
FOCUS: Echocardiography
IN THE CLINIC
The B-bump: A Marker for Elevated Left Ventricular End-Diastolic Pressure David G. Skolnick, MD and Douglas S. Segar, MD, Krannert Institute of Cardiology, Indiana University School of Medicine, Indianapolis, Indiana Elevated left ventricular end-diastolic pressure (LVEDP) is associated with symptoms of congestive heart failure (CHF). In patients with reduced systolic function, this finding is often a marker for poor prognosis. Even though echocardiography (echo) cannot make precise hemodynamic measurements, it can nevertheless offer significant insight into the relative filling pressures between the left ventricle (LV) and the left atrium (LA). Inferences concerning the diastolic filling pressure of the LV can be made by sampling transmitral inflow velocity with pulse-wave Doppler. Some of the limitations of this technique can be improved if it is used in conjunction with Doppler evaluation of the pulmonary veins. An alternative method is to study the diastolic motion of the mitral valve (MV) with M-mode in the parasternal long-axis. M-mode offers excellent temporal resolution and is able to detect a delay in MV closure. This delay is characterized by a B-bump and represents a LVEDP . 20 mm Hg (1). The normal M-mode pattern of the MV is shown in Figure 1. The E point represents early diastolic flow through the mitral valve and the A point represents flow due to atrial contraction. The onset of MV closure starts with atrial relaxation (2). Figure 1 also demonstrates the role of ventricular systole in closing the MV, when atrioventricular conduction is normal. The vertical line is placed on an R wave, the beginning of ventricular systole, which occurs during MV closure. The rise in ventricular pressure with systole creates a reversal in the transmitral pressure gradient and completes the process of valve closure. Note that the slope from the A point to the closure of the MV (C point) is steep and uninterrupted. Figure 2 illustrates the diastolic hemodynamics and Mmode tracings in both a normal ventricle (A) and a ventricle with reduced compliance (B). During diastole, the pressure in a normal LV rises gradually, even after atrial contraction. With a stiff ventricle, the pressures in both the LA and LV increase significantly and increase essentially in parallel. The point at which LV pressure exceeds that of the LA occurs sooner than normal (1). Consequently, the MV begins to close earlier. Due to the mechanics of a non-compliant
Figure 1. Normal appearing M-mode tracing of the anterior leaflet of the mitral valve imaged from the parasternal long-axis. ventricle, the LA pressure remains relatively high and the reversal in the transmitral pressure gradient is not sufficient to completely close the valve. The delay in valve closure interrupts the normally smooth slope from A to C, creating a B-bump. Since the original description of the B-bump, other investigators have suggested that the delay in MV closure is Figure 2. Diagrams illustrating how the mitral valve echocardiogram may reflect changes in left ventricular diastolic pressure. (From Feigenbaum, H. Echocardiography, 5th ed. Philadelphia: Lea & Febiger, 1994.)
ACC CURRENT JOURNAL REVIEW March/April 1998 © 1998 by the American College of Cardiology Published by Elsevier Science Inc.
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TECHNOLOGY SERIES
Figure 3. Parasternal long-axis views in end-diastole (A) and end-systole (B), in a patient with reduced systolic function. (C) Pulse-wave Doppler of transmitral inflow velocity. (D) M-mode tracing of the mitral valve, demonstrating a B-bump. due to end-diastolic mitral regurgitation (MR) (3,4). In either case, the B-bump is a qualitative sign identifying patients whose LVEDP is significantly elevated. It is a reasonably specific marker, but not a sensitive one (5). Figures 3A–D illustrate the clinical utility of a B-bump. The patient is a young woman who presented with a large anterior myocardial infarction, complicated by CHF. Figures 3A and 3B are end-diastolic and end-systolic views, respectively, demonstrating the markedly reduced systolic function. Only mild MR was present (not shown). The pulse-wave Doppler interrogation of the mitral inflow, Figure 3C, illustrates a classic restrictive pattern. The E/A ratio is much greater than 1 and deceleration time is , 150 milliseconds.
Clinically, this restrictive filling pattern is consistent with an elevated LVEDP due to severe systolic dysfunction. However, the transmitral Doppler pattern is often not as definitive as it is in this example. It may even appear normal in patients with deteriorating cardiac function. The differential diagnosis for a restrictive Doppler pattern includes severe MR, restrictive physiology or constrictive pericarditis. The M-mode tracing of the anterior mitral leaflet, Figure 3D, illustrates a typical appearing B-bump and confirms the presence of an elevated LVEDP. The vertical line in Figure 3D is again placed on an R wave. Note that the MV closure occurs during the B-bump and not on the down stroke following the A point (as seen in Figure 1). A potential look-alike to a B-bump is demonstrated in
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TECHNOLOGY SERIES
3. Ishikawa T, Usui T, Kashiwagi M, Kimura K, Yoshimura H, Sano T, Nihei T. Contribution of end-diastolic mitral regurgitation to the B-B’ Step Formation on M-mode echocardiography. J Applied Cardiol 1991;6:163–8. 4. Otsuji Y, Toda H, Ishigami T, Lee S, Okino H, Minagoe S, Nakao S, Tanaka H. Mitral Regurgitation During B Bump of the Mitral Valve Studied by Doppler Echocardiography. American Journal of Cardiology 1991;67: 778 – 80. 5. Feigenbaum H. Echocardiography. Philadelphia: Lea & Febiger, 1994:199. 6. Weyman A. Principles and Practice of Echocardiography. Philadelphia: Lea & Febiger, 1994:1253. Address correspondence and reprint requests to Douglas S. Segar, MD, Krannert Institute of Cardiology, 1111 West 10th Street, Indianapolis, IN 462024800.
Serial Follow-Up After Optimized UltrasoundGuided Deployment of Palmaz-Schatz Stents: In-Stent Neointimal Proliferation Without Significant Reference Segment Response H. Mudra, E. Regar, V. Klauss, F. Werner, K.-H. Henneke, E. Sbarouni, K. Theisen. Medizinische Klinik, Klinikum Innenstadt, Muenchen, Germany. Circulation 1997;95: 363–70. Background: The effects of ultrasound-guided high-pressure stenting on late stent and reference segment dimensions are unknown. In this study, we report about angiographic and ultrasound measurements to assess the amount and distribution of neointimal ingrowth within the stent and the changes of plaque burden and dimensions within the reference segments. Methods and Results: Sixty-eight consecutive patients with 72 lesions received single or multiple PalmazSchatz coronary stents with a standardized protocol for stent optimization under ultrasound guidance. The residual angiographic diameter stenosis was 3 6 12% (reference diameter, 3.16 6 0.61 mm). At follow-up 4.8 6 2.5 months later, angiography revealed a diameter stenosis of 27 6 21% with a restenosis rate of 15.3% (confidence interval: 7.8% to 25.6%). Lumen renarrowing within the stent was exclusively due to neointimal ingrowth; no stent compression was observed. The neointima covered 20 6 20% of the stent area and was more pronounced in the midportion of the stent. Volumetric assessment performed in 26 patients resulted in 13 6 14% of 62 6 28% of the stent volume occupied by neointimal ingrowth in patients without or with restenosis, respectively. Vessel remodeling had an impact on lumen dimensions only at reference sites but not within the stent. Plaque burden of 46 6 11% and 48 6 11% at the proximal and distal reference sites, respectively, did not show a relevant progression during the follow-up. Conclusions: Serial ultrasound analyses did not show any evidence of stent compression or relevant vessel remodeling. Restenosis was solely due to neointimal ingrowth. Despite a considerable plaque burden within the reference segments, there was no relevant progression of the disease adjacent to the stent.
Figure 4. M-mode interrogation (A) of the mitral valve in a patient with a markedly prolonged first-degree atrioventricular block (B). Figure 4A (lower white arrow). Note that the corresponding rhythm strip, Figure 4B, shows a markedly prolonged firstdegree atrioventricular block, with a PR interval of about 640 milliseconds. As mentioned above, MV closure is initiated with the fall in LA pressure during atrial relaxation. With sufficient prolongation of the PR interval, the MV closes before ventricular systole. However, when the PR interval is . 500 milliseconds, the MV typically reopens as LA pressure gradually rises due to pulmonary venous filling (6). The delay in MV closure, during normal atrioventricular conduction, is a manifestation of a non-compliant ventricle in the setting of an elevated end-diastolic pressure. Although a precise value cannot be assigned, the presence of a B-bump suggests that the LVEDP is at least 20 mm Hg. Careful interrogation of the anterior leaflet of the MV with M-mode offers an alternative or complementary method to transmitral pulse-wave Doppler to diagnose abnormal hemodynamics during diastole.
REFERENCES 1. Konecke LL, Feigenbaum H, Chang S, Corya BC, Fisher JC. Abnormal mitral valve motion in patients with elevated left ventricular diastolic pressure. Circulation 1973;47:989 –96. 2. Zaky A, Steinmetz E, Feigenbaum H. Role of atrium in closure of mitral valve in man. Am J Physiol 1969;217:1652–9.
ACC CURRENT JOURNAL REVIEW March/April 1998
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FOCUS: Echocardiography
IN THE CLINIC
The B-bump: A Marker for Elevated Left Ventricular End-Diastolic Pressure David G. Skolnick, MD and Douglas S. Segar, MD, Krannert Institute of Cardiology, Indiana University School of Medicine, Indianapolis, Indiana Elevated left ventricular end-diastolic pressure (LVEDP) is associated with symptoms of congestive heart failure (CHF). In patients with reduced systolic function, this finding is often a marker for poor prognosis. Even though echocardiography (echo) cannot make precise hemodynamic measurements, it can nevertheless offer significant insight into the relative filling pressures between the left ventricle (LV) and the left atrium (LA). Inferences concerning the diastolic filling pressure of the LV can be made by sampling transmitral inflow velocity with pulse-wave Doppler. Some of the limitations of this technique can be improved if it is used in conjunction with Doppler evaluation of the pulmonary veins. An alternative method is to study the diastolic motion of the mitral valve (MV) with M-mode in the parasternal long-axis. M-mode offers excellent temporal resolution and is able to detect a delay in MV closure. This delay is characterized by a B-bump and represents a LVEDP . 20 mm Hg (1). The normal M-mode pattern of the MV is shown in Figure 1. The E point represents early diastolic flow through the mitral valve and the A point represents flow due to atrial contraction. The onset of MV closure starts with atrial relaxation (2). Figure 1 also demonstrates the role of ventricular systole in closing the MV, when atrioventricular conduction is normal. The vertical line is placed on an R wave, the beginning of ventricular systole, which occurs during MV closure. The rise in ventricular pressure with systole creates a reversal in the transmitral pressure gradient and completes the process of valve closure. Note that the slope from the A point to the closure of the MV (C point) is steep and uninterrupted. Figure 2 illustrates the diastolic hemodynamics and Mmode tracings in both a normal ventricle (A) and a ventricle with reduced compliance (B). During diastole, the pressure in a normal LV rises gradually, even after atrial contraction. With a stiff ventricle, the pressures in both the LA and LV increase significantly and increase essentially in parallel. The point at which LV pressure exceeds that of the LA occurs sooner than normal (1). Consequently, the MV begins to close earlier. Due to the mechanics of a non-compliant
Figure 1. Normal appearing M-mode tracing of the anterior leaflet of the mitral valve imaged from the parasternal long-axis. ventricle, the LA pressure remains relatively high and the reversal in the transmitral pressure gradient is not sufficient to completely close the valve. The delay in valve closure interrupts the normally smooth slope from A to C, creating a B-bump. Since the original description of the B-bump, other investigators have suggested that the delay in MV closure is Figure 2. Diagrams illustrating how the mitral valve echocardiogram may reflect changes in left ventricular diastolic pressure. (From Feigenbaum, H. Echocardiography, 5th ed. Philadelphia: Lea & Febiger, 1994.)
ACC CURRENT JOURNAL REVIEW March/April 1998 © 1998 by the American College of Cardiology Published by Elsevier Science Inc.
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1062-1458/98/$19.00 PII S1062-1458(98)00008-7
TECHNOLOGY SERIES
Figure 3. Parasternal long-axis views in end-diastole (A) and end-systole (B), in a patient with reduced systolic function. (C) Pulse-wave Doppler of transmitral inflow velocity. (D) M-mode tracing of the mitral valve, demonstrating a B-bump. due to end-diastolic mitral regurgitation (MR) (3,4). In either case, the B-bump is a qualitative sign identifying patients whose LVEDP is significantly elevated. It is a reasonably specific marker, but not a sensitive one (5). Figures 3A–D illustrate the clinical utility of a B-bump. The patient is a young woman who presented with a large anterior myocardial infarction, complicated by CHF. Figures 3A and 3B are end-diastolic and end-systolic views, respectively, demonstrating the markedly reduced systolic function. Only mild MR was present (not shown). The pulse-wave Doppler interrogation of the mitral inflow, Figure 3C, illustrates a classic restrictive pattern. The E/A ratio is much greater than 1 and deceleration time is , 150 milliseconds.
Clinically, this restrictive filling pattern is consistent with an elevated LVEDP due to severe systolic dysfunction. However, the transmitral Doppler pattern is often not as definitive as it is in this example. It may even appear normal in patients with deteriorating cardiac function. The differential diagnosis for a restrictive Doppler pattern includes severe MR, restrictive physiology or constrictive pericarditis. The M-mode tracing of the anterior mitral leaflet, Figure 3D, illustrates a typical appearing B-bump and confirms the presence of an elevated LVEDP. The vertical line in Figure 3D is again placed on an R wave. Note that the MV closure occurs during the B-bump and not on the down stroke following the A point (as seen in Figure 1). A potential look-alike to a B-bump is demonstrated in
ACC CURRENT JOURNAL REVIEW March/April 1998
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TECHNOLOGY SERIES
3. Ishikawa T, Usui T, Kashiwagi M, Kimura K, Yoshimura H, Sano T, Nihei T. Contribution of end-diastolic mitral regurgitation to the B-B’ Step Formation on M-mode echocardiography. J Applied Cardiol 1991;6:163–8. 4. Otsuji Y, Toda H, Ishigami T, Lee S, Okino H, Minagoe S, Nakao S, Tanaka H. Mitral Regurgitation During B Bump of the Mitral Valve Studied by Doppler Echocardiography. American Journal of Cardiology 1991;67: 778 – 80. 5. Feigenbaum H. Echocardiography. Philadelphia: Lea & Febiger, 1994:199. 6. Weyman A. Principles and Practice of Echocardiography. Philadelphia: Lea & Febiger, 1994:1253. Address correspondence and reprint requests to Douglas S. Segar, MD, Krannert Institute of Cardiology, 1111 West 10th Street, Indianapolis, IN 462024800.
Serial Follow-Up After Optimized UltrasoundGuided Deployment of Palmaz-Schatz Stents: In-Stent Neointimal Proliferation Without Significant Reference Segment Response H. Mudra, E. Regar, V. Klauss, F. Werner, K.-H. Henneke, E. Sbarouni, K. Theisen. Medizinische Klinik, Klinikum Innenstadt, Muenchen, Germany. Circulation 1997;95: 363–70. Background: The effects of ultrasound-guided high-pressure stenting on late stent and reference segment dimensions are unknown. In this study, we report about angiographic and ultrasound measurements to assess the amount and distribution of neointimal ingrowth within the stent and the changes of plaque burden and dimensions within the reference segments. Methods and Results: Sixty-eight consecutive patients with 72 lesions received single or multiple PalmazSchatz coronary stents with a standardized protocol for stent optimization under ultrasound guidance. The residual angiographic diameter stenosis was 3 6 12% (reference diameter, 3.16 6 0.61 mm). At follow-up 4.8 6 2.5 months later, angiography revealed a diameter stenosis of 27 6 21% with a restenosis rate of 15.3% (confidence interval: 7.8% to 25.6%). Lumen renarrowing within the stent was exclusively due to neointimal ingrowth; no stent compression was observed. The neointima covered 20 6 20% of the stent area and was more pronounced in the midportion of the stent. Volumetric assessment performed in 26 patients resulted in 13 6 14% of 62 6 28% of the stent volume occupied by neointimal ingrowth in patients without or with restenosis, respectively. Vessel remodeling had an impact on lumen dimensions only at reference sites but not within the stent. Plaque burden of 46 6 11% and 48 6 11% at the proximal and distal reference sites, respectively, did not show a relevant progression during the follow-up. Conclusions: Serial ultrasound analyses did not show any evidence of stent compression or relevant vessel remodeling. Restenosis was solely due to neointimal ingrowth. Despite a considerable plaque burden within the reference segments, there was no relevant progression of the disease adjacent to the stent.
Figure 4. M-mode interrogation (A) of the mitral valve in a patient with a markedly prolonged first-degree atrioventricular block (B). Figure 4A (lower white arrow). Note that the corresponding rhythm strip, Figure 4B, shows a markedly prolonged firstdegree atrioventricular block, with a PR interval of about 640 milliseconds. As mentioned above, MV closure is initiated with the fall in LA pressure during atrial relaxation. With sufficient prolongation of the PR interval, the MV closes before ventricular systole. However, when the PR interval is . 500 milliseconds, the MV typically reopens as LA pressure gradually rises due to pulmonary venous filling (6). The delay in MV closure, during normal atrioventricular conduction, is a manifestation of a non-compliant ventricle in the setting of an elevated end-diastolic pressure. Although a precise value cannot be assigned, the presence of a B-bump suggests that the LVEDP is at least 20 mm Hg. Careful interrogation of the anterior leaflet of the MV with M-mode offers an alternative or complementary method to transmitral pulse-wave Doppler to diagnose abnormal hemodynamics during diastole.
REFERENCES 1. Konecke LL, Feigenbaum H, Chang S, Corya BC, Fisher JC. Abnormal mitral valve motion in patients with elevated left ventricular diastolic pressure. Circulation 1973;47:989 –96. 2. Zaky A, Steinmetz E, Feigenbaum H. Role of atrium in closure of mitral valve in man. Am J Physiol 1969;217:1652–9.
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