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Large Left Atrial “v” Waves After Mitral Valve Replacement
Large Left Atrial “v” Waves After Mitral Valve Replacement Noah Bunker, MD, and James A. DiNardo, MD
A
CASE OF A child who underwent repair of a complete AV canal (CAVC) early in life but continued to have AV valve dysfunction requiring a mitral valvuloplasty and, ultimately, mitral valve replacement is presented. Left atrial (LA) and pulmonary hypertension persisted despite normal prosthetic mitral valve function. The unusual finding of large LA “v” waves at the time of cardiac catheterization was believed to be consistent with the presence of a small and noncompliant left atrium and noncompliant pulmonary venous system. CASE REPORT A 9.4-kg female was diagnosed at birth with a mildly dominant right CAVC defect. The atrial septal defect (ASD) was a malaligned septum primum type defect accompanied by a hypoplastic left atrium. There was a parachute mitral valve (single papillary muscle) and a mildly hypoplastic left ventricle. The inlet ventricular septal defect (VSD) extended to the muscular septum. In addition, a persistent left superior vena cava, a patent ductus arteriosus (PDA), and congenital absence of the right upper lobe and right upper lobe pulmonary arteries were present. At 2 months of age, she underwent a PDA ligation and repair of the CAVC by using a 2-patch technique. The repair was complicated by a residual VSD and high-grade AV block that required placement of an epicardial DDD pacemaker. Progressively worsening tricuspid regurgitation, mitral regurgitation (MR), and mitral stenosis led to failure to thrive and persistent pulmonary and right ventricular (RV) hypertension. At 14 months, she underwent a mitral valvuloplasty that failed to improve her condition, and her mitral valve was ultimately replaced with a 17-mm St Jude Medical Hemodynamic Plus valve (St Jude Medical, Inc, St Paul, MN) 2 months later. The anterior muscular VSD was closed intraoperatively with a 23-mm CardioSEAL (NMT Medical, Inc, Boston, MA) occlusion device, and a tricuspid valvuloplasty was performed. The left superior vena cava was baffled directly to the right atrium to reduce the size of the coronary sinus, thereby minimizing external LA compression. An echocardiogram 1 week postoperatively revealed worsening of the right ventricle and pulmonary hypertension with an estimated RV pressure of 45 to 50 mmHg (0.5-0.75 systemic) and a mean tricuspid valve gradient of 11 to 13 mmHg. Mitral valve function was normal with a mean inflow gradient of 2 to 3 mmHg and no mitral regurgitation. Cardiac catheterization performed at 2½ years of age (Figs 1 and 2 and Table 1) revealed the following pressures of RV 65/14 mmHg, ascending aortic pressure of 60/40 mmHg, left pulmonary artery pressure of 69/39 mmHg, LA “v” of 22 mmHg, LA “a” of 11 mmHg, LA mean of 16 mmHg with a cardiac index of 3.4 L/min/m2, and pulmonary vascular resistance elevated at 10.3 Wood units. The tricuspid valve mean gradient was 6 to 8 mmHg, and the mitral valve mean gradient was 2 to 3 mmHg. The pulmonary vasculature was mildly responsive to nitric oxide.
Fig 1. Simultaneous LA and LV pressure traces showing the presence of a “v” wave with early diastolic equilibration of LA and LV pressures (“y” descent). The mean left atrial pressure is elevated as the result of the large “v” wave. No substantial mean mitral valve gradient is seen.
DISCUSSION
LA hypertension is a common cause of pulmonary hypertension. Elevated LA pressure is usually the result of impaired left ventricular (LV) systolic or diastolic dysfunction, mitral insufficiency, or mitral stenosis. In this patient, pulmonary hypertension and RV dysfunction were the result of a large “v” wave in the absence of LV or mitral valve dysfunction. The upstroke of the normal LA “v” wave occurs during ventricular systole and atrial diastole as pulmonary venous blood fills the left atrium against a closed mitral valve. The “y” descent of the “v” wave occurs during ventricular diastole after the opening of the mitral valve. Five factors influence the
From the Department of Anesthesia, Perioperative and Pain Medicine, Children’s Hospital Boston, Harvard Medical School, Boston, MA. Address reprint requests to James A. DiNardo, MD, Department of Anesthesia, Perioperative and Pain Medicine, Children’s Hospital Boston, 300 Longwood Ave, Boston, MA 02115. E-mail: james.dinardo@ childrens.harvard.edu © 2009 Elsevier Inc. All rights reserved. 1053-0770/09/2301-0012$36.00/0 doi:10.1053/j.jvca.2007.10.012 Key words: heart defects, congenital, mitral valve, atrial function, ventricular function, heart catheterization, hypertension, pulmonary
Journal of Cardiothoracic and Vascular Anesthesia, Vol 23, No 1 (February), 2009: pp 69-70
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BUNKER AND DINARDO
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valve replacement and after standard mitral valve replacement in the presence of “stiff left atrial syndrome.”1 The prominent LA “v” wave results because a small, stiff left atrium quickly fills and is unable to provide an adequate reservoir for pulmonary venous blood. Normally, the pulmonary veins are a very compliant reservoir and serve to dampen the effect of pulmonary venous blood flow on LA pressure. In children with chronically elevated LA pressure, increased muscularity and reduced compliance of the pulmonary venous vasculature can occur. Therefore, the authors believe that the cause of the persistent pulmonary hypertension in the present patient was the high-amplitude “v” waves with an elevated mean LA pressure as the result of a small, noncompliant left atrium and noncompliant pulmonary venous system. In conclusion, persistent pulmonary hypertension and large LA “v” waves may reflect underlying left atrium and pulmonary venous pathology rather than mitral valve or left ventricular dysfunction.
Fig 2. An LV angiogram during systole showing the absence of mitral valve regurgitation.
Table 1. Hemodynamic Catheterization Data Pressure (mmHg) (Sys/Dias or a/v/mean) Location
height and duration of the “v” wave: (1) volume of blood entering the atrium (either from the pulmonary veins or the LV if there is MR during ventricular systole, (2) rate of forward flow into the atrium, (3) compliance of the combined LA and pulmonary vein chambers, (4) systemic afterload, and (5) LV contractile force.1 Large LA “v” waves may occur in MR and have the greatest amplitude with acute MR when the left atrium is small and less distensible. In chronic MR, slow LA dilation occurs over time, and the “v” wave amplitude is reduced. Prominent LA “v” waves after mitral valve replacement previously have been reported after both supraannular mitral
RA RV PA (left) PCW (left) LA LV Aorta
Rest
Oxygen
Nitric Oxide
23/21/20 65/14 69/39/50 13 (mean) 14/20/15 71/14 60/40/47
22/22/21 74/16 66/36/48 14 (mean) 14/21/15 74/15 68/38/49
20/20/19 51/11 56/29/39 16 (mean) 14/22/16 77/18
Rest, room air; Oxygen, 100% FIO2; Nitric Oxide ⫽ 20 ppm inhaled nitric oxide. Abbreviations: Sys, systolic; Dias, diastolic; RA, right atrium; PA, pulmonary artery; PCW, pulmonary capillary wedge; LA, left atrium.
REFERENCE 1. Adatia I, Moore PM, Jonas RA, et al: Clinical course and hemodynamic observations after supraannular mitral valve replace-
ment in infants and children. J Am Coll Cardiol 29:1089-1094, 1997
A
CASE OF A child who underwent repair of a complete AV canal (CAVC) early in life but continued to have AV valve dysfunction requiring a mitral valvuloplasty and, ultimately, mitral valve replacement is presented. Left atrial (LA) and pulmonary hypertension persisted despite normal prosthetic mitral valve function. The unusual finding of large LA “v” waves at the time of cardiac catheterization was believed to be consistent with the presence of a small and noncompliant left atrium and noncompliant pulmonary venous system. CASE REPORT A 9.4-kg female was diagnosed at birth with a mildly dominant right CAVC defect. The atrial septal defect (ASD) was a malaligned septum primum type defect accompanied by a hypoplastic left atrium. There was a parachute mitral valve (single papillary muscle) and a mildly hypoplastic left ventricle. The inlet ventricular septal defect (VSD) extended to the muscular septum. In addition, a persistent left superior vena cava, a patent ductus arteriosus (PDA), and congenital absence of the right upper lobe and right upper lobe pulmonary arteries were present. At 2 months of age, she underwent a PDA ligation and repair of the CAVC by using a 2-patch technique. The repair was complicated by a residual VSD and high-grade AV block that required placement of an epicardial DDD pacemaker. Progressively worsening tricuspid regurgitation, mitral regurgitation (MR), and mitral stenosis led to failure to thrive and persistent pulmonary and right ventricular (RV) hypertension. At 14 months, she underwent a mitral valvuloplasty that failed to improve her condition, and her mitral valve was ultimately replaced with a 17-mm St Jude Medical Hemodynamic Plus valve (St Jude Medical, Inc, St Paul, MN) 2 months later. The anterior muscular VSD was closed intraoperatively with a 23-mm CardioSEAL (NMT Medical, Inc, Boston, MA) occlusion device, and a tricuspid valvuloplasty was performed. The left superior vena cava was baffled directly to the right atrium to reduce the size of the coronary sinus, thereby minimizing external LA compression. An echocardiogram 1 week postoperatively revealed worsening of the right ventricle and pulmonary hypertension with an estimated RV pressure of 45 to 50 mmHg (0.5-0.75 systemic) and a mean tricuspid valve gradient of 11 to 13 mmHg. Mitral valve function was normal with a mean inflow gradient of 2 to 3 mmHg and no mitral regurgitation. Cardiac catheterization performed at 2½ years of age (Figs 1 and 2 and Table 1) revealed the following pressures of RV 65/14 mmHg, ascending aortic pressure of 60/40 mmHg, left pulmonary artery pressure of 69/39 mmHg, LA “v” of 22 mmHg, LA “a” of 11 mmHg, LA mean of 16 mmHg with a cardiac index of 3.4 L/min/m2, and pulmonary vascular resistance elevated at 10.3 Wood units. The tricuspid valve mean gradient was 6 to 8 mmHg, and the mitral valve mean gradient was 2 to 3 mmHg. The pulmonary vasculature was mildly responsive to nitric oxide.
Fig 1. Simultaneous LA and LV pressure traces showing the presence of a “v” wave with early diastolic equilibration of LA and LV pressures (“y” descent). The mean left atrial pressure is elevated as the result of the large “v” wave. No substantial mean mitral valve gradient is seen.
DISCUSSION
LA hypertension is a common cause of pulmonary hypertension. Elevated LA pressure is usually the result of impaired left ventricular (LV) systolic or diastolic dysfunction, mitral insufficiency, or mitral stenosis. In this patient, pulmonary hypertension and RV dysfunction were the result of a large “v” wave in the absence of LV or mitral valve dysfunction. The upstroke of the normal LA “v” wave occurs during ventricular systole and atrial diastole as pulmonary venous blood fills the left atrium against a closed mitral valve. The “y” descent of the “v” wave occurs during ventricular diastole after the opening of the mitral valve. Five factors influence the
From the Department of Anesthesia, Perioperative and Pain Medicine, Children’s Hospital Boston, Harvard Medical School, Boston, MA. Address reprint requests to James A. DiNardo, MD, Department of Anesthesia, Perioperative and Pain Medicine, Children’s Hospital Boston, 300 Longwood Ave, Boston, MA 02115. E-mail: james.dinardo@ childrens.harvard.edu © 2009 Elsevier Inc. All rights reserved. 1053-0770/09/2301-0012$36.00/0 doi:10.1053/j.jvca.2007.10.012 Key words: heart defects, congenital, mitral valve, atrial function, ventricular function, heart catheterization, hypertension, pulmonary
Journal of Cardiothoracic and Vascular Anesthesia, Vol 23, No 1 (February), 2009: pp 69-70
69
BUNKER AND DINARDO
70
valve replacement and after standard mitral valve replacement in the presence of “stiff left atrial syndrome.”1 The prominent LA “v” wave results because a small, stiff left atrium quickly fills and is unable to provide an adequate reservoir for pulmonary venous blood. Normally, the pulmonary veins are a very compliant reservoir and serve to dampen the effect of pulmonary venous blood flow on LA pressure. In children with chronically elevated LA pressure, increased muscularity and reduced compliance of the pulmonary venous vasculature can occur. Therefore, the authors believe that the cause of the persistent pulmonary hypertension in the present patient was the high-amplitude “v” waves with an elevated mean LA pressure as the result of a small, noncompliant left atrium and noncompliant pulmonary venous system. In conclusion, persistent pulmonary hypertension and large LA “v” waves may reflect underlying left atrium and pulmonary venous pathology rather than mitral valve or left ventricular dysfunction.
Fig 2. An LV angiogram during systole showing the absence of mitral valve regurgitation.
Table 1. Hemodynamic Catheterization Data Pressure (mmHg) (Sys/Dias or a/v/mean) Location
height and duration of the “v” wave: (1) volume of blood entering the atrium (either from the pulmonary veins or the LV if there is MR during ventricular systole, (2) rate of forward flow into the atrium, (3) compliance of the combined LA and pulmonary vein chambers, (4) systemic afterload, and (5) LV contractile force.1 Large LA “v” waves may occur in MR and have the greatest amplitude with acute MR when the left atrium is small and less distensible. In chronic MR, slow LA dilation occurs over time, and the “v” wave amplitude is reduced. Prominent LA “v” waves after mitral valve replacement previously have been reported after both supraannular mitral
RA RV PA (left) PCW (left) LA LV Aorta
Rest
Oxygen
Nitric Oxide
23/21/20 65/14 69/39/50 13 (mean) 14/20/15 71/14 60/40/47
22/22/21 74/16 66/36/48 14 (mean) 14/21/15 74/15 68/38/49
20/20/19 51/11 56/29/39 16 (mean) 14/22/16 77/18
Rest, room air; Oxygen, 100% FIO2; Nitric Oxide ⫽ 20 ppm inhaled nitric oxide. Abbreviations: Sys, systolic; Dias, diastolic; RA, right atrium; PA, pulmonary artery; PCW, pulmonary capillary wedge; LA, left atrium.
REFERENCE 1. Adatia I, Moore PM, Jonas RA, et al: Clinical course and hemodynamic observations after supraannular mitral valve replace-
ment in infants and children. J Am Coll Cardiol 29:1089-1094, 1997