ACC/AHA guidelines for the management of patients with valvular heart disease. A report of the American College of Cardiology/American Heart Association. Task Force on Practice Guidelines (Committee on Management of Patients with Valvular Heart Disease)

Aortic valve replacement: current clinical practice and opportunities for quality improvement

This is a review of the current clinical practice and opportunities for quality improvement in aortic valve replacement surgery. The topics include trends and regional variation in procedure rates, and changes in the use of aortic valve replacement among the elderly. Recent developments guiding the choice of prosthetic valves and trends in in-hospital mortality rates for aortic valve surgery are summarized. Lastly, a discussion of topics relevant to clinical practice improvement including the implementation of clinical practice guidelines, the need for consensus on risk adjustment, better understanding of volume-outcome effects, and the opportunities for comprehensive assessment of aortic valve surgery.

The effect of valvular heart disease on maternal and fetal outcome of pregnancy

OBJECTIVES

The aim of this study was to evaluate the association between valvular heart disease (VHD) and maternal and fetal outcome in a relatively large group of patients by a comparison to a well-matched control group.

BACKGROUND

Available information regarding outcome of pregnancy in women with VHD is limited to either anecdotal reports or small series of patients without an appropriate control. A better understanding of the effects of valvular abnormalities on pregnancy outcome is of value for risk assessment and the design of a therapeutic plan.

METHODS

A retrospective evaluation was made of 66 pregnancies in 64 women with VHD cared for at a tertian-care center with a high-risk obstetrics/cardiology clinic and 66 individually selected normal pregnant women matched in age, ethnicity, obstetrical and medical history, time of initial prenatal care, and year of pregnancy.

RESULTS

Women with VHD had a significantly higher incidence of congestive heart failure (38% vs. 0%; p < 0.00001), arrhvthmias (15% vs. 0%, p = 0.002), initiation or increase of cardiac medications (41% vs. 2%, p < 0.0001), and hospitalizations (35% vs. 2%, p < 0.0001). Mortality, however, occurred in only one patient (2% vs. 0%, p = NS) with aortic stenosis (AS) and coarctation. Moreover, VHD also had an effect on fetal outcome, resulting in an increased preterm delivery (23% vs. 6%, p = 0.03), intrauterine growth retardation (21% vs. 0%, p < 0.0001), and a reduced birth weight (2,897 +/- 838 g vs. 3,366 +/- 515 g, p = 0.0003). Increased maternal morbidity and unfavorable fetal outcome were seen mostly in patients with moderate and severe mitral stenosis (MS) and AS.

CONCLUSIONS

Pregnancy in women with MS and AS is associated with marked increase in maternal morbidity and unfavorable effect on fetal outcome, which are related to severity of disease. Despite high maternal morbidity, mortality is rare.

Variability in treatment advice for elderly patients with aortic stenosis: a nationwide survey in The Netherlands

OBJECTIVE

To determine how the decisions of Dutch cardiologists on surgical treatment for aortic stenosis were influenced by the patient's age, cardiac signs and symptoms, and comorbidity; and to identify groups of cardiologists whose responses to these clinical characteristics were similar.

DESIGN

A questionnaire was produced asking cardiologists to indicate on a six point scale whether they would advise cardiac surgery for each of 32 case vignettes describing 10 clinical characteristics.

SETTING

Nationwide postal survey among all 530 cardiologists in the Netherlands.

RESULTS

52% of the cardiologists responded. There was wide variability in the cardiologists' advice for the individual case vignettes. Six groups of cardiologists explained 60% of the variance. The age of the patient was most important for 41% of the cardiologists; among these, 50% had a high and 50% a low inclination to advise surgery. A further 24% were influenced equally by the patient's age and by the severity of the aortic stenosis and its effect on left ventricular function; among these, 62% had a high and 38% a low inclination to advise surgery. Finally, 23% of the cardiologists were mainly influenced by the left ventricular function and 12% by the aortic valve area. The presence of comorbidity always played a minor role.

CONCLUSIONS

There were systematic differences among groups of cardiologists in their inclination to advise aortic valve replacement for elderly patients, as well as in the way their advice was influenced by the patients' characteristics. These results indicate the need for prospective studies to identify the best treatment for elderly patients according to their clinical profile.

Valvular Heart Disease in the Pregnant Patient

Anticoagulation for the pregnant patient with valve disease is problematic: both the underlying thrombotic disorder and the pharmacologic agents available for its treatment pose significant risks to the mother and fetus. There are no randomized controlled trial data available to guide decision-making for this patient population. Clinical treatment algorithms usually are derived from patient registries or case series with the obvious limitations of retrospective review, selection bias, historical controls, and small patient numbers. Prospective trials clearly are needed, but clinical research in the pregnant patient presents a myriad of ethical and legal challenges. Warfarin and unfractionated heparin, the mainstays of anticoagulant therapy, fall quite short in any analysis of efficacy and safety. There is an increasing use of low molecular weight heparins (LMWHs) in clinical practice but without evidence-based validation. Anticoagulant management of the pregnant patient must begin with full disclosure of the hazards and limitations of all forms of available treatments, preferably prior to conception. Treatment should be predicated on an assessment of the relative risks of thrombosis and hemorrhage. Careful monitoring and dosage adjustment are required throughout gestation, labor, delivery, and the puerperium.

Endocarditis in the Pediatric Population

Endocarditis is a rare, but potentially fatal process in children. Patients with congenital heart disease compose the majority of patients with endocarditis. Neonates and children with central venous catheters are an increasingly frequent group of patients diagnose with this disease. Rheumatic fever predisposing to endocarditis is unusual. Streptococcus viridans and Staphylococcus aureus are the most pervasive organisms associated with endocarditis, though others are becoming more frequent. Blood cultures should be obtained in febrile children with congenital heart disease before the administration of antibiotics. Echocardiography is useful in children with known endocarditis, and in children in whom there is a high level of clinical suspicion for endocarditis. Echocardiography is a poor screening tool for patients without clinical or bacteriologic evidence for endocarditis. Endocarditis prophylaxis for children with congenital heart disease (excluding a secundum atrial septal defect) before appropriate procedures is recommended.

Exercise echocardiography predicts development of left ventricular dysfunction in medically and surgically treated patients with asymptomatic severe aortic regurgitation

OBJECTIVE

To assess resting and exercise echocardiography for prediction of left ventricular dysfunction in patients with significant asymptomatic aortic regurgitation.

DESIGN

Cohort study of patients with aortic regurgitation.

SETTING

Tertiary referral centre specialising in valvar surgery.

PATIENTS

61 patients (38 men, 23 women; mean (SD) age 53 (14) years) with asymptomatic or minimally symptomatic aortic regurgitation and no known coronary artery disease; 35 were treated medically and 26 had aortic valve replacement.

INTERVENTIONS

Exercise echocardiography was used to evaluate ejection fraction, which was measured on the resting and post-stress images using the modified Simpson method. Patients with an increment of ejection fraction after exercise were denoted as having contractile reserve (CR+); those without an increment were labelled CR-.

MAIN OUTCOME MEASURES

Standard univariate and multivariate methods and receiver operating characteristic analyses were used to assess the ability of contractile reserve to predict follow up ejection fraction.

RESULTS

In the 35 medically treated patients, 13 of 21 (62%) with CR+ (mean (SD) ejection fraction increment 7 (3)%) had preserved ejection fraction on follow up. In the 14 patients with CR- (ejection fraction decrement 8 (4)%), 13 (93%) had a decrement of ejection fraction on follow up from 60 (5)% at baseline to 54 (3)% on follow up (p = 0.005). Age, resting left ventricular dimensions, medical treatment, aortic regurgitation severity, exercise capacity, and rate-pressure product were similar in both CR+ and CR- groups. Among the 26 surgical patients, 13 showed CR+ (ejection fraction increase 9 (5)%), all of whom had an increase in ejection fraction on follow up (from 49% to 59%). Of 13 surgical patients with CR- (ejection fraction decrease 7 (5)%), 10 (77%) showed the same or worse ejection fraction on postoperative follow up.

CONCLUSIONS

Contractile reserve on exercise echocardiography is a better predictor of left ventricular decompensation than resting indices in asymptomatic patients with aortic regurgitation. In patients undergoing aortic valve replacement, contractile reserve had a better correlation with resting ejection fraction on postoperative follow up. Measurement of contractile reserve may be useful to monitor the early development of myocardial dysfunction in asymptomatic patients with aortic regurgitation, and may help to optimise the timing of surgery.

[Practice Guidelines of the Spanish Society of Cardiology for the management of cardiac disease in pregnancy]

Maternal adaptation to pregnancy includes reproductive hormone interaction plasma, volume changes with an increase in total body water, vascular alterations with a decrease in systemic resistance and modifications associated with hypercoagulability. These explain, in part, the appearance of signs and symptoms, even in a normal pregnant woman, that are difficult to distinguish from those occurring in heart disease and why some cardiac abnormalities are not well tolerated during pregnancy. Cardiovascular abnormalities are considered the first non-obstetric cause of morbidity and mortality during pregnancy. Rheumatic and congenital heart diseases are currently the most frequent cardiopathy found in women of childbearing age, followed by hypertension, coronary artery disease and arrhythmia. Although pregnancy is well tolerated by most women with heart disease, there are some cardiovascular abnormalities which place the mother and the infant at extremely high risk: patients with congestive heart failure and severe cardiac dysfunction, pulmonary hypertension, cyanotic congenital heart disease, Marfan's syndrome, severe obstructive lesions of the left side of the heart, patients with prosthetic cardiac valves and antecedents of peripartum cardiomyopathy should be encouraged to avoid pregnancy and the interruption of pregnancy may be advisable in cases with great risk of disability or death. The most severe cardiopathies significantly increase the risk of fetal loss and the presence of a congenital cardiac abnormality in either parent increases the risk of congenital cardiac disease in the fetus. Medical care must be initiated early, prior to conception and women with cardiopathy should be informed of the possible risks of pregnancy to both the mother and fetus.

Immediate and long-term results of valve replacement for native and prosthetic valve endocarditis

BACKGROUND

The objective of the present study was to compare current results of prosthetic valve replacement following acute infective native valve endocarditis (NVE) with that of prosthetic valve endocarditis (PVE). Prosthetic valve replacement is often necessary for acute infective endocarditis. Although valve repair and homografts have been associated with excellent outcome, homograft availability and the importance of valvular destruction often dictate prosthetic valve replacement in patients with acute bacterial endocarditis.

METHODS

A retrospective analysis of the experience with prosthetic valve replacement following acute NVE and PVE between 1988 and 1998 was performed at the Montreal Heart Institute.

RESULTS

Seventy-seven patients (57 men and 20 women, mean age 48 +/- 16 years) with acute infective endocarditis underwent valve replacement. Fifty patients had NVE and 27 had PVE. Four patients (8%) with NVE died within 30 days of operation and there were no hospital deaths in patients with PVE. Survival at 1, 5, and 7 years averaged 80% +/- 6%, 76% +/- 6%, and 76% +/- 6% for NVE and 70% +/- 9%, 59% +/- 10%, and 55% +/- 10% for PVE, respectively (p = 0.15). Reoperation-free survival at 1, 5, and 7 years averaged 80% +/- 6%, 76% +/- 6%, and 76% +/- 6% for NVE and 45% +/- 10%, 40% +/- 10%, and 36% +/- 9% for PVE (p = 0.003). Five-year survival for NVE averaged 75% +/- 9% following aortic valve replacement and 79% +/- 9% following mitral valve replacement. Five-year survival for PVE averaged 66% +/- 12% following aortic valve replacement and 43% +/- 19% following mitral valve replacement (p = 0.75). Nine patients underwent reoperation during follow-up: indications were prosthesis infection in 4 patients (3 mitral, 1 aortic), dehiscence of mitral prosthesis in 3, and dehiscence of aortic prosthesis in 2.

CONCLUSIONS

Prosthetic valve replacement for NVE resulted in good long-term patient survival with a minimal risk of reoperation compared with patients who underwent valve replacement for PVE. In patients with PVE, those who needed reoperation had recurrent endocarditis or noninfectious periprosthetic dehiscence.

Outcomes 15 years after valve replacement with a mechanical versus a bioprosthetic valve: final report of the Veterans Affairs randomized trial

OBJECTIVES

The goal of this study was to compare long-term survival and valve-related complications between bioprosthetic and mechanical heart valves.

BACKGROUND

Different heart valves may have different patient outcomes.

METHODS

Five hundred seventy-five patients undergoing single aortic valve replacement (AVR) or mitral valve replacement (MVR) at 13 VA medical centers were randomized to receive a bioprosthetic or mechanical valve.

RESULTS

By survival analysis at 15 years, all-cause mortality after AVR was lower with the mechanical valve versus bioprosthesis (66% vs. 79%, p = 0.02) but not after MVR. Primary valve failure occurred mainly in patients <65 years of age (bioprosthesis vs. mechanical, 26% vs. 0%, p < 0.001 for AVR and 44% vs. 4%, p = 0.0001 for MVR), and in patients > or =65 years after AVR, primary valve failure in bioprosthesis versus mechanical valve was 9 +/- 6% versus 0%, p = 0.16. Reoperation was significantly higher for bioprosthetic AVR (p = 0.004). Bleeding occurred more frequently in patients with mechanical valve. There were no statistically significant differences for other complications, including thromboembolism and all valve-related complications between the two randomized groups.

CONCLUSIONS

At 15 years, patients undergoing AVR had a better survival with a mechanical valve than with a bioprosthetic valve, largely because primary valve failure was virtually absent with mechanical valve. Primary valve failure was greater with bioprosthesis, both for AVR and MVR, and occurred at a much higher rate in those aged <65 years; in those aged > or =65 years, primary valve failure after AVR was not significantly different between bioprosthesis and mechanical valve. Reoperation was more common for AVR with bioprosthesis. Thromboembolism rates were similar in the two valve prostheses, but bleeding was more common with a mechanical valve.

[Practice guidelines of the Spanish Society of Cardiology on endocarditis]

Infectious endocarditis is a disease which mainly involves the cardiac valves. It has a bad prognosis and is caused by a great variety of microorganisms. Prophylaxis is important although the effectiveness and the best way to achieve it remain unclear. Recommendations are herein presented. The diagnosis is based on clinical, bacteriological, and echocardiographic findings mainly based on Duke's criteria. Transthoracic and transesophageal echography are not only of diagnostic value but are also a tool to determine the therapy to follow. Antibiotic therapy should be selected according to the organisms isolated and their in vitro susceptibility. Guidelines for empirical antibiotic therapy in cases of negative cultures are also included. Lastly, indications and time for surgery are discussed.

Diagnostic testing

The results of cardiac tests must always be interpreted through the lens of pretest probabilities created by the history and the physical examination. Tests should be chosen with a clear diagnostic and prognostic purpose in mind. A clear understanding of the relationship between the history and physical examination and more technologic diagnostic testing improves the primary care physician's ability to evaluate potential cardiac disease in an efficient and cost-effective manner.

Predictors of outcome in severe, asymptomatic aortic stenosis

BACKGROUND

Whether to perform valve replacement in patients with asymptomatic but severe aortic stenosis is controversial. Therefore, we studied the natural history of this condition to identify predictors of outcome.

METHODS

During 1994, we identified 128 consecutive patients with asymptomatic, severe aortic stenosis (59 women and 69 men; mean [+/-SD] age, 60+/-18 years; aortic-jet velocity, 5.0+/-0.6 m per second). The patients were prospectively followed until 1998.

RESULTS

Follow-up information was available for 126 patients (98 percent) for a mean of 22+/-18 months. Event-free survival, with the end point defined as death (8 patients) or valve replacement necessitated by the development of symptoms (59 patients), was 67+/-5 percent at one year, 56+/-5 percent at two years, and 33+/-5 percent at four years. Five of the six deaths from cardiac disease were preceded by symptoms. According to multivariate analysis, only the extent of aortic-valve calcification was an independent predictor of outcome, whereas age, sex, and the presence or absence of coronary artery disease, hypertension, diabetes, and hypercholesterolemia were not. Event-free survival for patients with no or mild valvular calcification was 92+/-5 percent at one year, 84+/-8 percent at two years, and 75+/-9 percent at four years, as compared with 60+/-6 percent, 47+/-6 percent, and 20+/-5 percent, respectively, for those with moderate or severe calcification. The rate of progression of stenosis, as reflected by the aortic-jet velocity, was significantly higher in patients who had cardiac events (0.45+/-0.38 m per second per year) than those who did not have cardiac events (0.14+/-0.18 m per second per year, P<0.001), and the rate of progression of stenosis provided useful prognostic information. Of the patients with moderately or severely calcified aortic valves whose aortic-jet velocity increased by 0.3 m per second or more within one year, 79 percent underwent surgery or died within two years of the observed increase.

CONCLUSIONS

In asymptomatic patients with aortic stenosis, it appears to be relatively safe to delay surgery until symptoms develop. However, outcomes vary widely. The presence of moderate or severe valvular calcification, together with a rapid increase in aortic-jet velocity, identifies patients with a very poor prognosis. These patients should be considered for early valve replacement rather than have surgery delayed until symptoms develop.

Usefulness of transesophageal echocardiography in the assessment of aortic dissection

The acute dissection of the ascending aorta requires prompt and reliable diagnosis to reduce the high risk of mortality; in addition, prognosis is influenced by long-term complications. The aim of this article is to discuss transesophageal echocardiography (TEE) and (1) its diagnostic accuracy in the presurgical evaluation of patients, (2) its role in reducing time of diagnosis and surgery, and (3) its ability to reduce hospital mortality. TEE has also been tested as a screening method in the postsurgical follow-up of these patients. The retrospective investigation concerns a sample of 80 cases of acute dissection of the aorta, submitted for surgical intervention from April 1986 to February 1999. TEE has allowed a precise estimation of aortic diameters and optimal visualization of intimal flap and tear entry with a fine distinction between true and false lumen. A direct comparison of the results of TEE and of transthoracic echocardiography has demonstrated that some elements (visualization of flap and diameters in descending aorta, sites of entry and reentry, direction of jet trough intimal tears, phasic intimal flap movement, diastolic collapse of flap on the valvular plane, false lumen thrombosis, coronary involvement, intramural hematoma, and aortic fissuration) were identified only by TEE, whereas other additional diagnostic elements (cardiac tamponade, aortic valve insufficiency, left ventricular function) show a similar pattern of significance. Routine employment of this method has confirmed a reduction of hospitalization time (about 1.5 hours of waiting time), and hospital mortality has changed from 42.8% to 17.3%. In the follow-up of patients operated on for aortic dissection, fundamental information may be obtained from TEE (assessment of the progression of thrombosis in the false lumen with its complete obliteration and modifications in aortic diameter with a consequent, possible worsening of aortic valve insufficiency). In conclusion, our study demonstrated that TEE may provide fast and efficient detection of acute aortic dissection. In the postsurgical follow-up, TEE has confirmed detection of major complications that can influence long-term prognosis and may be proposed as a method with easy access-one that is repeatable and inexpensive for the screening of aortic dissection surgical patients.

Interventional therapy in heart failure management

The incidence and prevalence of congestive heart failure are rapidly increasing because of the progressive decrease in age-adjusted mortality rates for coronary artery disease and hypertensive heart disease, together with the progressive aging of the US population. Despite great advances in maximal medical therapy, most patients with symptomatic congestive heart failure can expect functional impairment, interludes of worsening symptomatology, and a shortened life span. Thus, it is appropriate to ask whether the interventional revolution that is under way for the management of ischemic cardiovascular disease can be applied with benefit to the management of congestive heart failure. The use of interventional therapies for the treatment of elderly patients with congestive heart failure caused by coronary artery disease, valvular heart disease, or renal vascular disease is addressed.

Echocardiography in the evaluation of systolic murmurs of unknown cause

PURPOSE

Systolic murmurs are common, and it is important to know whether physical examination can reliably determine their cause. Therefore, we prospectively assessed the diagnostic accuracy of a cardiac examination in patients without previous echocardiography who were referred for evaluation of a systolic murmur.

SUBJECTS AND METHODS

In 100 consecutive adults (mean [+/- SD] age of 58 +/- 22 years) who were referred for a systolic murmur of unknown cause, the diagnostic accuracy of the cardiac examination by cardiologists (without provision of clinical history, electrocardiogram, or chest radiograph) was compared with the results of echocardiography.

RESULTS

The echocardiographic findings included a normal examination (functional murmur) in 21 patients, aortic stenosis in 29 patients, mitral regurgitation in 30 patients, left or right intraventricular pressure gradient in 11 patients, mitral valve prolapse in 11 patients, ventricular septal defect in 4 patients, hypertrophic obstructive cardiomyopathy in 3 patients, and associated aortic regurgitation in 28 patients. In 28 (35%) of the 79 patients with organic heart disease, more than one abnormality was found; combined aortic and mitral valve disease was the most frequent combination (n = 22). The sensitivity of the cardiac examination was acceptable for detecting ventricular septal defect (100% [4 of 4]), isolated mitral regurgitation (88% [26 of 36]), aortic stenosis (71% [21 of 29]), and a functional murmur (67% [14 of 21]), but not for intraventricular pressure gradients (18% [2 of 11]), aortic regurgitation (21% [6 of 28]), combined aortic and mitral valve disease (55% [6 of 11]), and mitral valve prolapse (55% [12 of 22]). In 6 patients, the degree of aortic stenosis was misjudged on the clinical examination, mainly because of a severely diminished left ventricular ejection fraction. Significant heart disease was missed completely in only 2 patients.

CONCLUSION

In adults with a systolic murmur of unknown cause, a functional murmur can usually be distinguished from an organic murmur. However, the ability of the cardiac examination to assess the exact cause of the murmur is limited, especially if more than one lesion is present. Thus, echocardiography should be performed in patients with systolic murmurs of unknown cause who are suspected of having significant heart disease.

Intravenous thrombolytic treatment of mechanical prosthetic valve thrombosis: a study using serial transesophageal echocardiography

OBJECTIVE

We analyzed the results of intravenous thrombolytic treatment under transesophageal echocardiographic (TEE) guidance in prosthetic valve thrombosis.

BACKGROUND

Thrombotic occlusion of prosthetic valves continues to be an uncommon but serious complication. Intravenous thrombolytic treatment has been proposed as an alternative to surgical intervention.

METHODS

In a four-year period, 32 symptomatic patients with prosthetic valve related thrombosis underwent 54 thrombolytic treatment sessions for the treatment of 36 distinct episodes. All patients had low international normalized ratio values at the presentation. Transesophageal echocardiography was performed at baseline and repeated after each thrombolytic treatment session (total 98 TEE examinations). Streptokinase was used as the initial agent with a repeat dose given within 24 h when necessary. Recurrent thrombosis was treated either with tissue plasminogen activator or urokinase.

RESULTS

The initial success after first dose was only 53% (17/32) but increased up to 88% (28/32) after repeated thrombolytic sessions upon documentation of suboptimal results on TEE examination (p < 0.01). In addition, four asymptomatic patients with large thrombi were also successfully treated with single infusion. The TEE characteristics of thrombus correlated with clinical presentation and response to lytics. Success was achieved with single lytic infusion in 40% of the obstructive thrombi as compared with 75% of the nonobstructive ones (p < 0.05). The success rates of lytic treatment were similar for mitral versus aortic valves, and for tilting disk versus bileaflet valves. Rapid (3 h) and slow (15 to 24 h) infusion of streptokinase resulted in similar success rates. However, major complications (three patients) occurred only in the rapid infusion group.

CONCLUSION

In patients with prosthetic valve thrombosis, intravenous slow infusion thrombolysis given in discrete, successive sessions guided by serial TEE and transthoracic echocardiography can be achieved with a low risk of complications and a high rate of success.

Rate of change in aortic valve area during a cardiac cycle can predict the rate of hemodynamic progression of aortic stenosis

BACKGROUND

The ability to predict the rate of hemodynamic progression in an individual patient with valvular aortic stenosis has been elusive. The purpose of the present study was to evaluate whether the rate of change in aortic valve area (AVA) measured during the ejection phase of a cardiac cycle predicts the rate of hemodynamic progression in patients with asymptomatic aortic stenosis.

METHODS AND RESULTS

In 84 adults with initially asymptomatic aortic stenosis and a baseline AVA of > or =0.9 cm(2), annual echocardiographic data were obtained prospectively (mean follow-up 2.8+/-1.3 years). With the initial echocardiogram, the ratio of AVA measured at mid-acceleration and mid-deceleration to the AVA at peak velocity was calculated. The primary outcome variable was the annual rate of change in AVA (rate of progression), with rate of progression classified as rapid (a reduction in AVA of > or =0.2 cm(2)/y) or slow (<0.2 cm(2)/y). Rapid progression was significantly associated with an AVA ratio of > or =1.25 (P=0.004, risk ratio 3.1, 95% CI 1.2 to 7.9). The sensitivity, specificity, and positive predictive value of AVA ratio of > or =1.25 for the prediction o rapid progression of valvar aortic stenosis was 64%, 72%, and 80% respectively. The decrease in ejection fraction measured from the initial to final echocardiogram was small but greater for patients with an AVA ratio of > or =1.25 (-4+/-7% versus +2+/-7%, P<0.001).

CONCLUSIONS

A flow-dependent change in AVA can be measured during a routine transthoracic echocardiographic study. The rate of change in AVA is an additional measure of disease severity and may be used to predict an individual's risk for subsequent rapid disease progression.

Aortic Regurgitation

Left ventricular (LV) systolic function is an important determinant of long-term prognosis in patients with chronic aortic regurgitation (AR). Impaired LV systolic function identifies a group of patients who are at risk of developing postoperative congestive heart failure and death after aortic valve replacement (AVR). Hence, asymptomatic patients with definite evidence of impaired LV function should undergo operation without waiting for the development of symptoms or more severe LV dysfunction. Among asymptomatic patients with normal LV systolic function (normal ejection fraction), prognosis is excellent, and fewer than 5% per year require surgery because of symptom development or LV dysfunction. Patients likely to require surgery can be identified on the basis of age, severity of LV dilatation, and progressive increase in LV dimensions or decrease in resting ejection fraction during the course of serial follow-up studies. Afterload-reducing therapy in asymptomatic patients with severe AR and normal LV function has beneficial hemodynamic effects; chronic therapy may reduce the likelihood of symptoms or LV systolic dysfunction. Aortic valve replacement should be performed once significant symptoms develop. In the absence of important symptoms, the operation should also be performed in patients with AR who manifest consistent and reproducible evidence of either LV contractile dysfunction at rest or extreme LV dilatation. Noninvasive imaging should play a major role in evaluation. An important clinical decision--such as recommending AVR in the asymptomatic patient--should not be based on a single echocardiographic or radionuclide angiographic measurement. When these data consistently indicate impaired contractile function at rest or extreme LV dilatation on repeat measurement, however, operation is indicated in the asymptomatic patient. This strategy should reduce the likelihood of irreversible LV dysfunction in these patients and enhance long-term postoperative survival.

Mitral Regurgitation

Chronic severe mitral regurgitation is a surgically correctable disorder. Advances in cardiac surgery (including mitral valve repair and less invasive operations), a low postoperative complication rate, and improved long-term prognosis have reduced the threshold for surgical referral. Choosing the optimal timing for surgery remains the cardinal problem. Clinical and diagnostic imaging information is essential to the detection of occult myocardial decompensation, for which surgical correction should be sought. Surgery is not generally recommended in asymptomatic patients without signs of progressive disease. The final decision regarding timing of surgery should be made based on all the clinical data, the patient's choice, and the available surgical expertise. The use of medical therapy to delay the time to surgery is not supported by large trials; however, small short-term studies of chronic vasodilator therapy show favorable hemodynamic effects.

Rheumatic Mitral Stenosis

Patients with symptomatic mitral stenosis should undergo evaluation with transthoracic and transesophageal echocardiography (Table 1). Those patients with suitable valve morphology should be treated with percutaneous transvenous mitral commissurotomy (PTMC). Randomized trials of catheter commissurotomy have shown no differences in long-term outcome compared with surgical commissurotomy; there is therefore no role for surgical commissurotomy in patients who are suitable candidates for balloon commissurotomy. Mitral valve replacement should be recommended for those patients with valve deformity too severe to undergo catheter therapy. Some older patients who are less-than-ideal candidates for catheter therapy nonetheless may benefit from it as a palliative alternative to otherwise high-risk valve surgery. Asymptomatic patients should be screened for the presence of pulmonary artery hypertension. Those who have pulmonary artery systolic pressure at rest of greater than 50 mm Hg or who develop pulmonary artery systolic pressure of greater than 60 mm Hg with exercise should be considered for PTMC.

Aortic Stenosis

Choice of the best surgical option for aortic stenosis (AS) must be individualized and requires discussion among patient, cardiologist, and surgeon to weigh the risks and benefits of different options. Mechanical valves have been preferred for young patients, for those with a life expectancy of more than 10 to 15 years, or for those who require anticoagulation. Bioprosthetic valves have been preferred for elderly patients, for patients with limited life expectancy, or for patients who are unable to be anticoagulated. Newer tissue valves (eg, the stentless porcine aortic bioprosthesis and homografts) as well as newer techniques (eg, the Ross procedure) have increased the number of available options and the complexity of the decision-making process.

Pregnancy outcomes and cardiac complications in women with mechanical, bioprosthetic and homograft valves

OBJECTIVES

Firstly, to compare pregnancy outcomes and cardiac complications in women with: 1) either mechanical or bioprosthetic valves at the mitral site; 2) mechanical valves treated with warfarin or subcutaneous heparin. Secondly, to determine pregnancy and cardiac outcomes in women with aortic homograft valves.

DESIGN

Historical cohort study.

SETTING

Greenlane Hospital, Auckland, New Zealand.

POPULATION

Young women (n = 255) who had valve replacements between 1972 and 1992. Seventy-nine women underwent 147 pregnancies.

MAIN OUTCOME MEASURES

Pregnancy loss, cardiac complications.

RESULTS

Pregnancy loss occurred in 59% of pregnancies with mitral mechanical valves (n = 50) and 7% with mitral bioprosthetic valves (n = 33) (RR 8 x 20, 95% CI 2 x 10-31 x 93). Pregnancy loss rate was 70% in pregnancies treated with warfarin, compared with 25% for those switched from warfarin to heparin (RR 2 x 81, 95% CI 1 x 03-7 x 73). All heparin-associated losses occurred in the first trimester, whereas there were four stillbirths with warfarin. Cardiac complications occurred in 10 pregnancies (20%) in the women with mitral mechanical valves and four (13%) with mitral bioprosthetic valves (RR 1 x 55, 95% CI 0 x 53-4 x 52). All four thromboembolic complications with mechanical valves occurred in the 14 women treated with heparin throughout pregnancy. Structural valve deterioration occurred in four pregnancies (10%) with mitral bioprosthetic valves. No cardiac complications or known pregnancy losses occurred with aortic homograft valves (n = 41).

CONCLUSION

The high pregnancy loss rate in women with mitral mechanical valves was associated with warfarin throughout pregnancy, whereas the thromboembolic cardiac complications were associated with heparin. Pregnancy outcome was very good in women with bioprosthetic and homograft valves.

Prevalence of valvular-regurgitation associated with dexfenfluramine three to five months after discontinuation of treatment

OBJECTIVES

The goal of this study was to determine the prevalence of valvular regurgitation and abnormal valve morphology in patients three to five months after discontinuation of dexfenfluramine (Dexfen) therapy.

BACKGROUND

We previously reported the results of a randomized, double-blind, placebo-controlled trial of valvular structure and function in 1,073 patients treated either with Dexfen, with an investigational sustained-release dexfenfluramine (Dexfen SR), or with a placebo, with echocardiograms performed approximately one month from the last dose. Using FDA criteria (aortic regurgitation [AR] > or =mild and/or mitral regurgitation [MR] > or =moderate) we found no statistical difference among the groups, but when all degrees of valvular regurgitation were considered and when the two Dexfen groups were combined, there was a higher prevalence of any degree of AR, any degree of MR, and restricted posterior mitral leaflet mobility. However, it was unknown whether these differences in prevalence persisted.

METHODS

The double blind was maintained, and all patients were invited to return for a follow-up echocardiogram. Echocardiograms were acquired using a standardized protocol and assessed blindly to determine the degree of valvular regurgitation and valve leaflet thickness and mobility. We had an 80% power to detect a statistically significant change in paired proportions using the McNemar test (alpha = 0.05).

RESULTS

Echocardiograms were obtained on 941 patients with a median of 137 days after drug discontinuation. Aortic regurgitation (of any degree) was present in 13.8% of Dexfen (p = 0.41 compared to placebo), 10.7% of Dexfen SR (p = 0.64 compared to placebo), and 11.9% of placebo patients. The minor differences between patients treated with active drug versus placebo, which were found in the previous study, were no longer significant even when the groups were combined (p = 0.83 compared to placebo). Mitral regurgitation (of any degree) was present in 71.5% (p = 0.15 compared to placebo), 69.8% (p = 0.30 compared to placebo), and 70.5%, respectively. This was also not significantly different from placebo when both Dexfen groups were combined (p = 0.16). There was no difference in the prevalence of restricted posterior mitral leaflet mobility among the three groups (p = 0.19).

CONCLUSIONS

The small increase in prevalence of minor degrees of AR and MR in patients treated with two to three months of Dexfen previously reported is no longer present three to five months after discontinuation of medication. These data suggest that the degree of regurgitation observed in patients who used Dexfen for a relatively short duration does not progress over time.

Assessing the severity of mitral stenosis: variability between noninvasive and invasive measurements in patients with symptomatic mitral valve stenosis

BACKGROUND

This study evaluated the correlation and variability between noninvasive and invasive measures of mitral stenosis severity before and after balloon mitral commissurotomy (BMC) in a large group of patients with symptomatic mitral stenosis. Factors related to variability between measurements were determined.

METHODS

The Doppler transmitral gradient, Doppler half-time valve area, and 2-dimensional echocardiographic (2D) mitral valve area (MVA) were measured immediately before and 1 day after BMC in 272 consecutive patients with mitral stenosis and compared with their respective measures during cardiac catheterization.

RESULTS

The correlation coefficient for the comparison of noninvasive and invasive measurements of the transmitral gradient was 0.63 before BMC and 0.60 after the procedure; for 2D versus Gorlin-derived MVA, 0.39 and 0.57, respectively; and for Doppler half-time versus Gorlin-derived MVA, 0.31 and 0.18, respectively. A large degree of variability in the measurement of MVA was present among the 3 techniques before BMC and increased after BMC. Before BMC, for the comparison of 2D and Gorlin-derived MVA, variables predictive of the discrepancy were age, echocardiographic score, transmitral gradient during catheterization, and cardiac index. For the comparison of Doppler half-time versus Gorlin-derived MVA, age, heart rate during cardiac catheterization and echocardiography, cardiac output and left ventricular end-diastolic pressure predicted the difference between the 2 measures.

CONCLUSIONS

In symptomatic patients with mitral stenosis, there is significant variability between noninvasive and invasive measures of mitral stenosis severity despite careful, reproducible measurements. The difference between noninvasive and invasive measures of MVA before BMC is strongly related to cardiac output.

Interventional Cardiology: Advances in Percutaneous Techniques for the Treatment of Cardiac Disease

The field of interventional cardiology began in the late 1970s and consisted primarily of balloon catheter angio plasty until the early 1990s. Although understanding of the process of coronary angioplasty has evolved signifi cantly, restenosis still remains the Achilles' heel of the interventional cardiologist. This article reviews the cur rent issues involved in interventional cardiology for coronary disease from patient selection, anticoagulant therapy, restenosis, current interventional devices (stent mania), and future devices (intracoronary radiation). Noncoronary interventional procedures, vaivuloplasty, and atrial septal defect closure are also reviewed to provide an overview of cardiac interventional proce dures for the anesthesiologist.