Joseph F. Malouf

Outcome of 622 Adults With Asymptomatic, Hemodynamically Significant Aortic Stenosis During Prolonged Follow-Up

Background—This study assessed the long-term outcome of a large, asymptomatic population with hemodynamically significant aortic stenosis (AS). Methods and Results—We identified 622 patients with isolated, asymptomatic AS and peak systolic velocity ≥4 m/s by Doppler echocardiography who did not undergo surgery at the initial evaluation and obtained follow-up (5.4±4.0 years) in all. Mean age (±SD) was 72±11 years; there were 384 (62%) men. The probability of remaining free of cardiac symptoms while unoperated was 82%, 67%, and 33% at 1, 2, and 5 years, respectively. Aortic valve area and left ventricular hypertrophy predicted symptom development. During follow-up, 352 (57%) patients were referred for aortic valve surgery and 265 (43%) patients died, including cardiac death in 117 (19%). The 1-, 2-, and 5-year probabilities of remaining free of surgery or cardiac death were 80%, 63%, and 25%, respectively. Multivariate predictors of all-cause mortality were age (hazard ratio [HR], 1.05; P<0.0001), chronic renal failure (HR, 2.41; P=0.004), inactivity (HR, 2.00; P=0.001), and aortic valve velocity (HR, 1.46; P=0.03). Sudden death without preceding symptoms occurred in 11 (4.1%) of 270 unoperated patients. Patients with peak velocity ≥4.5 m/s had a higher likelihood of developing symptoms (relative risk, 1.34) or having surgery or cardiac death (relative risk, 1.48). Conclusions—Most patients with asymptomatic, hemodynamically significant AS will develop symptoms within 5 years. Sudden death occurs in ≈1%/y. Age, chronic renal failure, inactivity, and aortic valve velocity are independently predictive of all-cause mortality.

Choice of computed tomography, transesophageal echocardiography, magnetic resonance imaging, and aortography in acute aortic dissection: International Registry of Acute Aortic Dissection (IRAD).

For acute aortic dissection, CT is selected most frequently worldwide as the initial test, followed by TEE. Aortography and MRI are performed much less often. More than two thirds of the patients required ≥2 imaging tests.

Impact of Prosthesis-Patient Mismatch on Long-Term Survival in Patients With Small St Jude Medical Mechanical Prostheses in the Aortic Position

Background— The impact of aortic prosthesis-patient mismatch (P-PtM) on long-term survival is unclear. Methods and Results— Between 1985 and 2000, 388 patients at Mayo Clinic in Rochester, Minn, underwent aortic valve replacement (AVR) with 19- or 21-mm St Jude Medical prostheses and had transthoracic echocardiography within 1 year after AVR. Mean age of patients was 62±13 years; 69% were female. Prosthesis effective orifice area (EOA) was derived from the continuity equation. P-PtM was classified as severe (indexed EOA ≤0.60 cm2/m2), moderate (0.60 cm2/m20.85 cm2/m2). P-PtM was severe in 66 patients (17%), moderate in 168 (43%), and not hemodynamically significant in 154 (40%). Patients with severe P-PtM had a significantly larger body surface area (P<0.0001), higher mean gradient (P<0.0001), lower preoperative (P<0.0001) and postoperative (P<0.0001) ejection fractions, and lower stroke volume (P<0.0001) and more often received a 19-mm prosthesis (P=0.0008) than patients with moderate or no hemodynamically significant mismatch. For patients with severe mismatch, 5-year survival rates (72±6%) and 8-year survival rates (41±8%) were significantly less than for patients with moderate mismatch (80±3% and 65±5%; P=0.026) or no hemodynamically significant mismatch (85±3% and 74±5%; P=0.002). On multivariate analysis after adjustment for other predictors of outcome, severe mismatch was associated with higher mortality (hazard ratio 2.18; 95% confidence interval 1.24 to 3.85; P=0.007) and higher incidence of congestive heart failure (hazard ratio 3.1; 95% confidence interval 1.3 to 7.4; P=0.009) than no hemodynamically significant mismatch. Conclusions— Severe P-PtM is an independent predictor of higher long-term mortality and congestive heart failure in patients with small St Jude Medical aortic valve prostheses. For patients undergoing AVR who are at risk of severe mismatch, every effort should be made to use a larger prosthesis or to consider a prosthesis with a larger EOA.

Flow-Gradient Patterns in Severe Aortic Stenosis With Preserved Ejection Fraction Clinical Characteristics and Predictors of Survival

Background— Among patients with severe aortic stenosis (AS) and preserved ejection fraction, those with low gradient (LG) and reduced stroke volume may have an adverse prognosis. We investigated the prognostic impact of stroke volume using the recently proposed flow-gradient classification. Methods and Results— We examined 1704 consecutive patients with severe AS (aortic valve area <1.0 cm2) and preserved ejection fraction (≥50%) using 2-dimensional and Doppler echocardiography. Patients were stratified by stroke volume index (<35 mL/m2 [low flow, LF] versus ≥35 mL/m2 [normal flow, NF]) and aortic gradient (<40 mm Hg [LG] versus ≥40 mm Hg [high gradient, HG]) into 4 groups: NF/HG, NF/LG, LF/HG, and LF/LG. NF/LG (n=352, 21%), was associated with favorable survival with medical management (2-year estimate, 82% versus 67% in NF/HG; P<0.0001). LF/LG severe AS (n=53, 3%) was characterized by lower ejection fraction, more prevalent atrial fibrillation and heart failure, reduced arterial compliance, and reduced survival (2-year estimate, 60% versus 82% in NF/HG; P<0.001). In multivariable analysis, the LF/LG pattern was the strongest predictor of mortality (hazard ratio, 3.26; 95% confidence interval, 1.71–6.22; P<0.001 versus NF/LG). Aortic valve replacement was associated with a 69% mortality reduction (hazard ratio, 0.31; 95% confidence interval, 0.25–0.39; P<0.0001) in LF/LG and NF/HG, with no survival benefit associated with aortic valve replacement in NF/LG and LF/HG. Conclusions— NF/LG severe AS with preserved ejection fraction exhibits favorable survival with medical management, and the impact of aortic valve replacement on survival was neutral. LF/LG severe AS is characterized by a high prevalence of atrial fibrillation, heart failure, and reduced survival, and aortic valve replacement was associated with improved survival. These findings have implications for the evaluation and subsequent management of AS severity.

Severe pulmonary hypertension in patients with severe aortic valve stenosis: Clinical profile and prognostic implications

OBJECTIVES We analyzed the clinical characteristics and outcomes of 47 patients with severe pulmonary hypertension (PHT) and severe aortic valve stenosis (AS) from 1987 to 1999. BACKGROUND The prognostic implications of severe pulmonary hypertension in patients with severe AS are poorly understood. METHODS The mean age of patients was 78 years (range 47 to 91 years), and 37 patients (79%) were in New York Heart Association (NYHA) functional class III or IV. Aortic valve replacement (AVR) was performed in 37 patients (79%) and 10 patients (21%) were treated conservatively. RESULTS In the group that had AVR, there were six perioperative deaths (16%) and nine late deaths, resulting in a total mortality of 32%. In the conservatively treated group, there were eight deaths (80%) on follow-up. Severe PHT was an independent predictor of perioperative mortality. However, perioperative mortality was independent of the severity of left ventricular systolic dysfunction or concomitant coronary artery bypass grafting. Aortic valve replacement was associated with significant improvement in left ventricular ejection fraction, the severity of PHT and NYHA functional class. The difference between long-term survival of the operative survivors and the expected survival from life tables was not statistically significant. CONCLUSIONS The prognosis for patients with AS and severe PHT treated conservatively without AVR is dismal. Although AVR is associated with higher than usual mortality, the potential benefits outweigh the risk of surgery.

Mycotic aneurysms of the thoracic aorta: A diagnostic challenge

Mycotic aneurysm of the thoracic aorta is rare but can be fatal if not diagnosed early (1). The epidemiology of this disease is changing. Bacterial endocarditis, which was once the main cause, now accounts for the minority of cases reported (2– 4), and a tendency for the disease to occur in the elderly has been observed (2,5). Staphylococcus aureus and Salmonella species are the predominant organisms (2,4), although immunosuppressed patients and those who use intravenous drugs are susceptible to many opportunistic organisms (3,6,7). Presenting symptoms are often nonspecific, reflecting uncontrolled systemic sepsis and the insidious nature of the disease (6,8). However, the first clinical manifestation is often the sequela of aneurysm expansion (4) or rupture (6). Surgery remains the definitive treatment, but perioperative mortality can be as high as 63% in patients with aneurysm rupture (2). Still, the reported clinical experience is limited to a few small series and case reports (1,4,5,9 –11). We review our experience with 11 patients seen at Mayo Clinic over 25 years.

Sex differences in aortic valve calcification measured by multidetector computed tomography in aortic stenosis

Background—Aortic valve calcification (AVC) is the intrinsic mechanism of valvular obstruction leading to aortic stenosis (AS) and is measurable by multidetector computed tomography. The link between sex and AS is controversial and that with AVC is unknown. Methods and Results—We prospectively performed multidetector computed tomography in 665 patients with AS (aortic valve area, 1.05±0.35 cm2; mean gradient, 39±19 mm Hg) to measure AVC and to assess the impact of sex on the AVC–AS severity link in men and women. AS severity was comparable between women and men (peak aortic jet velocity: 4.05±0.99 versus 3.93±0.91 m/s, P=0.11; aortic valve area index: 0.55±0.20 versus 0.56±0.18 cm2/m2; P=0.46). Conversely, AVC load was lower in women versus men (1703±1321 versus 2694±1628 arbitrary units; P<0.0001) even after adjustment for their smaller body surface area or aortic annular area (both P<0.0001). Thus, odds of high-AVC load were much greater in men than in women (odds ratio, 5.07; P<0.0001). Although AVC showed good associations with hemodynamic AS severity in men and women (all r>0.67; P<0.0001), for any level of AS severity measured by peak aortic jet velocity or aortic valve area index, AVC load, absolute or indexed, was higher in men versus women (all P⩽0.01). Conclusions—In this large AS population, women incurred similar AS severity than men for lower AVC loads, even after indexing for their smaller body size. Hence, the relationship between valvular calcification process and AS severity differs in women and men, warranting further pathophysiological inquiry. For AS severity diagnostic purposes, interpretation of AVC load should be different in men and in women.

Reoperation for prosthetic aortic valve obstruction in the era of echocardiography: trends in diagnostic testing and comparison with surgical findings.

OBJECTIVES We sought to: 1) identify trends in the diagnostic testing of patients with prosthetic aortic valve (AVR) obstruction who undergo reoperation and 2) compare diagnostic test results with pathologic findings at surgery. BACKGROUND It is unclear whether Doppler transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) have reduced hemodynamic catheterization rates. METHODS We reviewed 92 consecutive cases ofAVR reoperation at a single center from 1989 to 1998, comparing 49 cases of mechanical AVR obstruction (group A) to 43 cases of bioprosthetic obstruction (group B). Preoperative Doppler TTE was performed in all cases. RESULTS In group A cases, there was a marginally significant trend towards lower catheterization rates for the Gorlin AVR area, from 36% in 1989 to 1990 to 10% in 1997 to 1998 (p = 0.07), but diagnostic TEE utilization (47% of cases) did not vary. The cause of mechanical AVR obstruction was pannus in 26 cases (53%), mismatch (P-PM) in 19 (39%) and thrombosis in 4 (8%). The mechanism (pannus/thrombus vs. mismatch) was identified in 10% by TTE and 49% by TEE (p < 0.001). In group B cases, hemodynamic catheterization rates (21%) and diagnostic TEE utilization (21%) did not vary with time. Obstruction was caused by structural degeneration in 37 cases (86%), thrombosis in 3 (7%), mismatch in 2 (5%) and pannus in 1 (2%). The mechanism was correctly identified in 63% by TTE and in 81% by TEE (p = 0.18). CONCLUSIONS Doppler TTE is the primary means to diagnose AVR obstruction; hemodynamic catheterization is not routinely needed. In unselected patients with mechanical AVR obstruction, TEE differentiation of pannus or thrombus from mismatch is challenging.

Survival by stroke volume index in patients with low-gradient normal EF severe aortic stenosis

Objective Low-gradient (LG) severe aortic stenosis (AS) and preserved EF with reduced stroke volume are associated with an adverse prognosis, but the relationship of stroke volume index (SVI) with mortality among a range of values is unknown. We investigated the prognostic impact of SVI in this population. Methods We examined 405 consecutive patients with preserved EF (≥50%) and severe AS (valve area <1.0 cm2) with LG (<40 mm Hg) using echocardiography. Patients were stratified into quartiles based on SVI distribution (group 1: <38 mL/m2 (n=90), group 2: 38–43 mL/m2 (n=105), group 3: 43–48 mL/m2 (n=104) and group 4: >48 mL/m2 (n=106)). Results Groups 1 and 2 had poorer survival with medical management compared with 3 and 4 (3-year estimate 46% and 67% vs. 78% and 73%, respectively, p=0.002) although aortic valve replacement referral rate was similar (53%–62%, p=0.57). An inverse relationship was observed between SVI and mortality (HR 1.28 (1.11 to 1.46) per every 5 mL/m2 decrease in SVI). After multivariable analysis, SVI was the strongest predictor of mortality (HR 0.92 (0.89 to 0.95), p<0.0001). Using different SVI cutpoints, SVI <35 was associated with highest mortality (HR 2.36 (1.49 to 3.73), p<0.001), followed by SVI <38 (HR 2.09 (1.39 to 3.16), p<0.001) and by SVI <43 (HR 2.05 (1.38 to 3.05), p<0.001). Survival with SVI ≥43 was similar to age and sex-matched controls (3-year estimate 84%, p=0.24); survival for SVI <43 was significantly worse (3-year estimate 63%, p<0.001). Conclusions Lower SVI is incrementally associated with mortality in LG severe AS with preserved EF. These findings have implications for classification of AS severity, identification of high-risk groups and subsequent management.

Clinical Outcome of Asymptomatic Severe Aortic Stenosis With Medical and Surgical Management: Importance of STS Score at Diagnosis

BACKGROUND The Society of Thoracic Surgeons (STS) score aims at predicting operative mortality in cardiac surgery. The value of this score in predicting short- and long-term survival with medical or surgical management in patients with asymptomatic severe aortic stenosis (AS) is unknown. METHODS In a cohort of 694 patients (aged 71 ± 11 years) with isolated, asymptomatic severe AS (velocity ≥4 m/s), STS score was calculated at baseline and its link to survival analyzed. Patients were stratified by STS score less than 4%, 4% to 6.5%, and 6.5% or greater. RESULTS The STS score showed no association with operative mortality within 1 year of diagnosis or any time (1%, 2.9%, and 6.1%, respectively, by strata; p = 0.08) and a weak association with 1-year survival (p = 0.04). Conversely, long-term survival (10-year) was strongly predicted by STS score strata (78%, 47%, and 16%, respectively; p < 0.0001). In multivariate analysis, STS score independently predicted mortality (hazard ratio/1%, 1.15 [1.12 to 1.18], p < 0.0001) or cardiac death (1.21 [1.17 to 1.25], p < 0.0001). Aortic valve replacement within 1 year of diagnosis markedly improved survival (adjusted hazard ratio, 0.58, p < 0.001). However, benefit of early surgery varied according to strata, with no overt benefit with low score (p = 0.83), whereas early surgery considerably improved survival in the intermediate strata (p < 0.001). CONCLUSIONS For patients with asymptomatic severe AS, STS score is a powerful tool for predicting long-term outcome and for selecting patients (particularly those at intermediate risk) who benefit markedly from early surgery. Hence, risk-scoring using STS score should be routinely performed in patients with AS to support the clinical decision-making process.