Natural history of aortic and mitral valve disease

An appreciation of the natural history of acquired valvular heart disease is a prerequisite to an understanding of how surgical intervention has altered the natural outlook. The prognosis for a patient with valvular heart disease treated medically is dependent on the stage of the disease at which he is first seen. Therefore, assessment for surgery requires evaluation of the pathophysiologic consequences that have resulted from the hemodynamic alterations. Survival statistics for patients seen at the University of California Medical Center at San Francisco are presented and compared with the data of others. Stenotic lesions appear to have a poorer prognosis than chronic regurgitant lesions and generally warrant surgical intervention at an earlier functional stage of the disease. However, valvular insufficiency produced acutely is poorly tolerated and may constitute a surgical emergency.     

Restoration and maintenance of sinus rhythm after mitral valve surgery for mitral stenosis

The preoperative clinical, echocardiographic, hemodynamic and surgical data were studied from 40 consecutive patients with pure mitral stenosis and chronic atrial fibrillation who underwent surgical correction of mitral stenosis. After surgery, the patients had cardioversion of atrial fibrillation. The data of 24 patients who maintained sinus rhythm (SR) for more than 3 months (success group) were compared with the data of the 16 patients who failed to maintain SR for more than 3 months (failure group). The patients in the success group were younger (mean age 38 ± 12 vs 47 ± 13 years, p < 0.05), had symptoms for a shorter time (3.0 ± 4.3 vs 6.4 ± 5.0 years, p < 0.02) and had a smaller preoperative echocardiographic left atrial (LA) size (4.9 ± 0.9 vs 5.5 ± 1.0 cm, p < 0.03). The correlation between duration of SR after cardioversion (range 0 to 12 months) and the preoperative data were examined with the use of the “all-possible-subsets-regression” software. The best subset of predictors of successful cardioversion included echocardiographic LA size, functional capacity, duration of symptoms and echocardiographic left ventricular fractional shortening. Patients with symptoms for more than 3 years and echocardiographic LA size of more than 5.2 cm had low rate of successful cardioversion; in this subset of patients, postoperative cardioversion should be avoided.     

Primary cardiomyopathy in identical twins

Seventeen year old identical twin brothers with no family history of cardiopathy began experiencing palpitations almost simultaneously. In both, examination revealed marked cardiomegaly and hypokinesia of the ventricular walls, and clinical and radiologic signs of progressive cardiac failure developed a few days later. Both boys died suddenly, 49 days and 5 months, respectively, after the initial examination. Electrocardiographic and vectorcardiographic studies revealed a severe intraventricular conduction disturbance that coincided with histologic changes in the myocardial tissue, including profuse interstitial fibrosis, hypertrophy and degeneration of the myocardial fibers, aberrant arrangement of the muscular fibers and considerable alteration of the structure of cardiac tissue. In the absence of hereditary and chromosomal factors, and excluding possible viral intervention during fetal life, it is believed that a teratogenic factor can produce the structural alterations of the tissue and derangement of the fibers observed in these hearts.The irregular contractions of the heart at the level of the net-like meshwork, disarrangement of myocardial fibers, and adaptative mechanisms of the heart inherent in the destruction of the contractile tissue contributed to the functional cardiac disorders that resulted in congestive heart failure and sudden death in these twins.     

Association of ostium secundum atrial septal defects with mitral valve prolapse

Severe prolapse of the mitral valve leaflets was seen at left ventricular angiography in 16 of 92 patients with a secundum type atrial septal defect studied prospectively from 1970 to 1974. The patients were aged 15 to 69 years; angioplasty or mitral valve replacement was carried out in nine. In 9 of 122 patients aged 15 to 55 years who were operated on for closure of a secundum type atrial septal defect between 1956 and 1969, mitral regurgitation due to prolapse but with intact chordae tendineae was seen at operation. In three of these patients chordal rupture was seen at a second operation 2 to 6 years later. The outlook in the syndrome of mitral valve prolapse may be less benign than is usually believed.     

The natural history of aortic valve disease after mitral valve surgery

OBJECTIVES

The present study evaluates the long-term course of aortic valve disease and the need for aortic valve surgery in patients with rheumatic mitral valve disease who underwent mitral valve surgery.

BACKGROUND

Little is known about the natural history of aortic valve disease in patients undergoing mitral valve surgery for rheumatic mitral valve disease. In addition there is no firm policy regarding the appropriate treatment of mild aortic valve disease while replacing the mitral valve.

METHODS

One-hundred thirty-one patients (44 male, 87 female; mean age 61 ± 13 yr, range 35 to 89) were followed after mitral valve surgery for a mean period of 13 ± 7 years. All patients had rheumatic heart disease. Aortic valve function was assessed preoperatively by cardiac catheterization and during follow-up by transthoracic echocardiography.

RESULTS

At the time of mitral valve surgery, 59 patients (45%) had mild aortic valve disease: 7 (5%) aortic stenosis (AS), 58 (44%) aortic regurgitation (AR). At the end of follow-up, 96 patients (73%) had aortic valve disease: 33 AS (mild or moderate except in two cases) and 90 AR (mild or moderate except in one case). Among patients without aortic valve disease at the time of the mitral valve surgery, only three patients developed significant aortic valve disease after 25 years of follow-up procedures. Disease progression was noted in three of the seven patients with AS (2 to severe) and in six of the fifty eight with AR (1 to severe). Fifty two (90%) with mild AR remained stable after a mean follow-up period of 16 years. In only three patients (2%) the aortic valve disease progressed significantly after 9, 17 and 22 years. In only six patients of the entire cohort (5%), aortic valve replacement was needed after a mean period of 21 years (range 15 to 33). In four of them the primary indication for the second surgery was dysfunction of the prosthetic mitral valve.

CONCLUSIONS

Our findings indicate that, among patients with rheumatic heart disease, a considerable number of patients have mild aortic valve disease at the time of mitral valve surgery. Yet most do not progress to severe disease, and aortic valve replacement is rarely needed after a long follow-up period. Thus, prophylactic valve replacement is not indicated in these cases.     

Early systolic closure of the aortic valve in patients with hypertrophic subaortic stenosis and discrete subaortic stenosis. Correlation with preoperative and postoperative hemodynamics

Patterns of motion of the aortic valve were analyzed with echocardiography in 9 patients with discrete subaortic stenosis and 31 patients with idiopathic hypertrophic subaortic stenosis, 22 with and 9 without a resting intraventricular pressure gradient. The intention was to determine whether the early systolic closure of the aortic valve was a sensitive indicator of a resting pressure gradient across the left ventricular outflow tract. All 9 patients with discrete subaortic stenosis and the 22 patients with idiopathic hypertrophic subaortic stenosis with a resting pressure gradient showed early systolic closure of the aortic valve; however, the 9 patients without a resting gradient had normal motion of the aortic valve. Measured values for O-ESC (the interval from the opening point of the aortic valve to the point of early systolic closure of the aortic valve) in 9 patients with discrete subaortic stenosis and in 22 with idiopathic hypertrophic subaortic stenosis averaged 0.05 ± 0.01 (standard deviation) second and 0.14 ± 0.04 second for each group, respectively (P < 0.01). Twelve patients with idiopathic hypertrophic subaortic stenosis underwent operation to alleviate left ventricular outflow tract obstruction. In eight of these patients the resting pressure gradient was completely abolished and early systolic closure of the aortic valve was no longer present. The results indicate that in idiopathic hypertrophic subaortic stenosis, early systolic closure of the aortic valve is recorded only when there is a significant intraventricular pressure gradient at rest. The time of occurrence of early systolic closure differentiated patients with discrete subaortic stenosis from those with idiopathic hypertrophic subaortic stenosis in all observations.     

Early risks of open heart surgery for mitral valve disease.

During 1972 and 1973, a total of 235 patients had open heart surgery for mitral valve disease unassociated with significant aortic or rheumatic tricuspid valve disease. Thirty-one underwent closed heart mitral commissurotomy, without mortality. Of the 204 patients undergoing open operation, 125 had sequential measurement of cardiac output and mixed venous oxygen pressure. The hospital mortality rate was 6.4 percent in the larger group of 204 patients and in the 125 with cardiac output measurements. The rate was greater in those with class IV disability (New York Heart Association criteria) preoperatively than in those with class III or II disability. The mean +/- standard deviation of the average cardiac index early postoperatively was 2.05 +/- 0.579 liters-min--1-m--2. Cardiac index was lower in the patients who died early postoperatively than in those who did not. The probability of hospital death was a significant function of cardiac index. The predicted probability of death was 10 percent with an average cardiac index of 1.42 liters-min--1-m--2 and increased sharply with lower indexes. Cardiac index was lower early postoperatively than preoperatively, and was lower in patients in class IV than in those in class III. There was no significant difference in cardiac index between patients with mitral valve replacement and those in repair. A history of closed commissurotomy, age, duration of cardiopulmonary bypass, duration of cardiac ischemia and method of myocardial preservation did not significantly influence cardiac index or hospital mortality rate. There was no significant relation between mixed venous oxygen pressure and hospital death. Further improvement in results of mitral valve surgery requires adequate preservation of left ventricular performance before, during and after operation.     

Coronary arteriography and atrial thrombosis in mitral valve disease

The arteriographic findings of neovascularity and fistula formation from the coronary arteries to the left atrium have occasionally been reported in association with atrial thrombosis in patients with mitral valve disease. To establish the diagnostic value of these findings, the preoperative coronary angiograms of 507 patients who underwent open mitral valve surgery were reviewed. Atrial thrombosis was present in 76 patients (14.9 percent). In the 30 patients with angiographic neovascularity and fistula formation, the thrombi were always observed to arise from the circumflex coronary artery. None of these 30 patients had atherosclerotic coronary lesions. In 25 of these patients an atrial thrombus was found at operation.These coronary arteriographic findings, in this selected group of patients, had a predictive accuracy of 83.3 percent, a specificity of 98.8 percent and a sensitivity of 32.8 percent for the diagnosis of the presence of thrombus in the left atrium. No relation was found between these signs and the size and histologic age of the thrombl examined.     

Cardiac function during rest and exercise in patients with mitral valve prolapse: Role of radionuclear angiocardiography

The clinical features of mitral valve prolapse syndrome and ischemic coronary disease overlap, making differentiation of the two conditions difficult. Furthermore, many patients have both conditions. This study assessed changes in ventricular function during rest and exercise in patients with mitral valve prolapse alone and in patients with prolapse and concomitant coronary artery disease. Twelve patients with angiographically documented mitral valve prolapse and normal coronary anatomy and 11 patients with normal coronary anatomy and no mitral valve prolapse had increased ejection fraction and demonstrated no wall motion abnormality during exercise. Changes in ventricular function during exercise in 11 additional patients with mitral valve prolapse demonstrated on echocardiography were similar to those in the group with mitral valve prolapse and normal coronary anatomy seen on angiography. In contrast, 6 of 11 patients with mitral valve prolapse and coronary arterial stenosis demonstrated on angiography had a decreased ejection fraction and exhibited wall motion abnormalities during exercise. These results suggest that mitral valve prolapse alone has no detrimental effect on ventricular function during rest and exercise and that exercise-induced abnormalities in ventricular function are related to the presence and severity of coronary artery disease and not to mitral valve prolapse.     

Supravalvular mitral stenosis associated with tetralogy of Fallot.

The association of tetralogy of Fallot with supravalvular mitral stenosis is a rare anomaly that has been reported only once previously. The difficulty of preoperative diagnosis is emphasized. Although left-sided obstructive lesions in association with tetralogy of Fallot are rare, their recognition is imperative since these are surgically correctable anomalies and potentially lethal, as proved in this case and the one previously reported.     

Surgical experience in patients with Marfan's syndrome, ascending aortic aneurysm and aortic regurgitation.

Surgical treatment of cardiovascular complications in patients with Marfan's syndrome is usually recommended with apprehension since the systemic nature of the disease predisposes to early and late complications. To define the incidence of these complications, 30 patients were evaluated after surgical treatment of aortic insufficiency and ascending aortic aneurysm at the Texas Heart Institute. To provide a minimal follow-up period of 5 years, only patients operated upon during of before 1968 were included in this series. There were 9 female and 21 male patients aged 4 to 80 years (mean 44 years). Aortic insufficiency was treated by valvuloplasty in 3 patients and by aortic valve replacement in 27. Graft replacement of the ascending aorta was required in 23 patients, and the aneurysm was excised and the aorta repaired by direct anastomosis in 7. Two patients were lost to follow-up study; 12 of the remaining 28 (42.8 percent) lived 5 years or more. The hospital mortality rate was 20 percent (6 of 30); the causes of death included dissection or rupture of the aorta in three patients, congestive heart failure in two and pulmonary embolism in one. The 24 survivors lived from 5 weeks to 9 years. Follow-up data were available on 22 of these patients. Ten of these (45.4 percent) died of late complications. Seven died suddenly, four of these had redissection, one patient had occlusion of the right coronary artery, and two had ventricular fibrillation of no apparent cause. The remaining three died of noncardiac causes. Although the risk of ascending aortic and aortic valve surgery in patients with Marfan's syndrome is high, 42.8 percent of the patients in our series survived 5 years or more. We believe that surgery should be recommended for patients with Marfan's disease who have dissection of the aorta or severe aortic regurgitation, or both.     

Two-dimensional echocardiographic findings in double orifice mitral valve

Between December 1981 and April 1984, five children ranging in age from 1 month to 5 1/2 years examined by two-dimensional echocardiography appeared to have a double orifice mitral valve. The diagnosis was verified in one patient at surgery, one patient by angiography and one patient by necropsy. Associated malformations included mitral stenosis and regurgitation, coarctation of the aorta, ostium primum and secundum atrial septal defect, ventricular septal defect and hypoplastic left heart syndrome. Three varieties of double orifice mitral valve were observed: an incomplete bridge type (one patient), in which a small strand of tissue connected the anterior and posterior leaflets at the leaflet edge level; a complete bridge type (three patients), in which a fibrous bridge divided the atrioventricular orifice completely into equal or unequal parts and a hole type (one patient), in which an additional orifice with subvalvular apparatus occurred in the posterior commissure of the mitral valve. These three types could be distinguished by sweeping the transducer in cross-sectional view from the apex toward the base of the heart. Both orifices could be seen throughout the scan in the complete bridge type while in the incomplete bridge type the two orifices could be seen only at the level of the papillary muscles. In the hole type, the second orifice was seen at about midleaflet level. In all three types, the chordae surrounding each orifice attached to only one papillary muscle. Congenital mitral stenosis or regurgitation was evident in three patients. The type of the double orifice mitral valve did not predict the presence or severity of symptoms.     

Coronary sinus blood flow at rest and during isometric exercise in patients with aortic valve disease: Mechanism of angina pectoris in presence of normal coronary arteries

In 46 patients with aortic valve disease, coronary sinus blood flow was measured using a continuous thermodilution method both at rest and during isometric handgrip excercise. All patients had normal coronary angiograms. The patients were separated into three groups: Group I, 12 patients with aortic stenosis (systolic gradient 72 ± 12 mm Hg); Group II, 15 patients with both aortic stenosis and regurgitation; Group III, 19 patients with aortic regurgitation. At rest, the coronary sinus blood flow was two to three times normal. However, when corrected for left ventricular mass (ml/100 g), flow was within normal limits. The ratio diastolic pressure-time index/systolic pressure-time index ($\text{DPTI}\text{SPTI}$) was decreased in all three groups at rest. During isometric exercise, coronary sinus blood flow increased significantly: by 60 percent in Group I, by 88 percent in Group II and by 118 percent in Group III. There was a significant reduction of the $\text{DPTI}\text{SPTI}$ ratio.Of the 18 patients with angina on effort during the test, 7 were in Group I, 6 in Group II and 5 in Group III. There were no differences in the coronary sinus blood flow between the patients with angina and those who were pain-free, either at rest or during exercise. Angina pectoris does not appear to be caused by a failure of coronary blood flow to increase. There was no discrepancy between myocardial demand, as measured by the pressure-time index and coronary blood flow. However, the $\text{DPTI}\text{SPTI}$ ratio was significantly lower during exercise in the patients with angina than in those who were pain-free. Underperfusion of the subendocardial muscle seems to be a causative factor in the patients with angina.     

Natural history of patients with single-vessel disease suitable for percutaneous transluminal coronary angioplasty

To permit comparison of percutaneous transluminal coronary angioplasty (PTCA) with conventional therapy, the clinical outcome was established in patients who would have been suitable candidates for PTCA but who presented before the technique was available. Coronary angiograms were reviewed of patients who met the following criteria: single-vessel disease with proximal subtotal coronary stenosis, chest pain of at least class II, and cardiac catheterization before 1981. Angiograms were evaluated according to established criteria for PTCA by an experienced angiographer. One hundred ten patients (2.1% of the patient population) were judged suitable for PTCA. Clinical and catheterization findings closely resembled those of patients in the national PTCA registry. Five years after catheterization, 97% of PTCA candidates treated medically were alive and 85% had not had myocardial infarction. Forty-six patients had coronary artery bypass surgery within 6 months of catheterization and 10 other patients had subsequent surgery. Five years after surgery, 91% were alive and 87% had not had myocardial infarction. At 6 months of follow-up, 78% of all patients had improved at least 1 functional class, and 86% of all patients working before catheterization were still employed. Functional capacity was well maintained during long-term follow-up (median 6.5 years, range 1.4 to 12.2). These data indicate that PTCA candidates have an excellent prognosis for survival, a low risk of infarction, and well-maintained functional capacity when revascularization is reserved for those with inadequate control of symptoms by medical therapy.     

Reliability and reproducibility of two dimensional echocardiograph measurement of the stenotic mitral valve orifice area.

A wide angle phased array sector scanner was used to find the optimal method, the reliability and the reproducibility of measuring the mitral valve area with two dimensional echocardiography in patients with rheumatic mitral stenosis. Initial experience with 18 patients revealed that tracing the early diastolic actual black-white interface of the perceived orifice was the most reliable method for drawing the mitral valve orifice area. Good interobserver correlation was obtained when two observers used either method to calculate the mitral valve area (r = 0.93). Similarly good intrastudy reliability was obtained when any one observer applied one measurement method to different diastolic cycles within the same study (r = 0.89). The phased array two dimensional echocardiogram properly differentiated patients with critical mitral stenosis from those with non-critical mitral stenosis, but the correlation between the echocardiographically and the hemodynamically derived mitral valve areas was less good than previously reported (r = 0.83). Imaging a test object with varied known orifice sizes and excised stenotic mitral valves of known orifice size with a phased array and mechanical sector scanner failed to reveal superiority of either instrument. Further testing with a phased array instrument revealed that the perceived orifice was critically dependent on receiver gains settings for any transmitted power level. Receiver gain settings too low led to image dropout, indicating a falsely large orifice. Receiver gain settings too high led to image saturation, indicating a falsely narrowed orifice. Six additional patients with predominant mitral stenosis later underwent imaging with strict attention paid to individual receiver gain settings. Combining the data from these 6 patients with those from the initial 18 patients gave a better correlation between the echocardiographic and hemodynamic calculated mitral valve areas (r = 0.92).Accurate noninvasive measurement of the mitral valve area with two dimensional echocardiography in patients with mitral stenosis appears to depend on use of the proper echocardiographic technique to localize the true commissural edge of the valve in early diastole, the correct instrument settings and the appropriate method for drawing the perceived orifice. The noninvasive measurement of the mitral valve orifice with two dimensional echocardiography in mitral stenosis provides clinically useful data that are reliable and reproducible if these factors are taken into account.