The progression rate of aortic stenosis: key to tailoring the management and potential target for treatment

Factors Affecting Rate of Progression of Aortic Stenosis and Its Impact on Outcomes

The rate of aortic stenosis (AS) progression in patients with moderate AS is unclear. This study examined the risk factors of progression from moderate to severe AS and its impact on clinical outcomes. A total of 954 patients with moderate AS (valve area >1.0 and ≤1.5 cm²) and follow-up echocardiograms were included. AS progressed to severe (valve area <1.0 cm¹) in 589 patients (61.7%) over a median follow-up of 2.46 (interquartile range [IQR] 1.29 to 3.91) years. Of those who progressed to severe AS, patients were subdivided into Slow (n = 294, over 3.91 [IQR 3.11 to 5.10] years) versus Fast (n = 295, over 1.29 [IQR 0.85 to 1.85] years) Progressors, according to the median time between the 2 echocardiograms. The correlates of fast AS progression and its impact on cumulative survival and freedom from valve intervention were evaluated. On multivariate analysis, age, thickened left ventricle posterior wall, severe renal impairment, and aortic valve area were significantly associated with fast AS progression. Over a median follow-up of 6.34 (IQR 4.05 to 9.55) years, 228 patients (38.7%) died. Despite similar aortic valve intervention rates, Fast Progressors had worse 5-year survival (61.2% vs 81.9%, log-rank p <0.001) and event-free (valve intervention and all-cause mortality) survival rates (16.2% vs 55.9%, log-rank p <0.001). On multivariable Cox analysis, shorter progression to severe AS (in years) was independently associated with increased risk of all-cause mortality (hazard ratio 1.26, 95% confidence interval 1.16 to 1.37, p <0.001), or combined aortic valve intervention and death (hazard ratio 1.46, 95% confidence interval 1.38 to 1.55, p <0.001). In conclusion, fast progression from moderate to severe AS is associated with worse outcomes.

Usefulness of the Right Parasternal Echocardiographic View to Improve the Hemodynamic Assessment After Valve Replacement for Aortic Stenosis

Right-parasternal-view (RPV) often provides the best hemodynamic assessment of the aortic-valve-stenosis by echocardiography. However, no detailed study on patients with aortic prosthesis is available. Thus, RPV usefulness is left as an anecdotical notion in this context. We aimed to define feasibility and clinical-impact of RPV before and soon-after percutaneous implantation (TAVI) or surgical (SAVR) aortic-valve-replacement (AVR) for AS. Patients with severe-AS electively referred for AVR between September-2019 and February-2020 were prospectively evaluated. Echocardiographic examinations inclusive of apical and RPV to measure aortic-peak-velocity , gradients and area (AVA) were performed the day before AVR and at hospital discharge and compared by matched-pair-analysis. Forty-seven patients (mean age 79 ± 8 years, 63% female, ejection-fraction 61 ± 6%) referred for SAVR (24 [51%]) or TAVI (23 [49%]) were enrolled. RPV was feasible in 45 patients (96%) before-AVR but in only 32 after-AVR (68%), particularly after SAVR (50%) than TAVI (87% p = 0.005). RPV remained the best acoustic window after TAVI in 75% of cases. Hemodynamic assessment of TAVI, but not SAVR, invariably benefit from RPV versus apical evaluation (aortic-peak-velocity: 2.57 ± 0.39 vs 2.23 ± 0.47 m/sec, p = 0.002; mean gradient: 15 ± 5 vs 12 ± 5 mm Hg, p = 0.01). Five (11%) patients presented severe patient-prosthesis-mismatch, 4 of which were detectable only by RPV. This pilot-experience demonstrates that RPV feasibility is slightly reduced after AVR. RPV can improve the hemodynamic assessment of the prosthetic valve versus apical view, including the detection of patient-prosthesis-mismatch. Furthermore, when RPV is the best acoustic windows in patients with severe AS, it generally remains so after-TAVI.

Excess Mortality Associated with Progression Rate in Asymptomatic Aortic Valve Stenosis

BACKGROUND

Aortic valve stenosis (AS) is a progressive condition characterized by gradual calcification of the aortic cusps. Progression rate evaluated using echocardiography has been associated with survival. However, data from routine practice covering the whole spectrum of AS severity and the rate of symptom onset are sparse. The aim of this study was to assess outcomes under medical management related to disease progression in asymptomatic patients with a wide range of AS severity.

METHODS

Two hundred twenty-nine consecutive asymptomatic patients (mean age, 77 ± 10 years; 55% men) with AS, preserved left ventricular ejection fraction, and two or more echocardiographic examinations performed from 2004 to 2014 were retrospectively included. The median time between the two echocardiographic examinations was 24 months (interquartile range, 15-46 months). Patients were identified as rapid progressors if the annualized difference in peak aortic velocity between two echocardiographic examinations was ≥0.3 m/sec/y; others were labeled as slow progressors. The primary end point was mortality during medical follow-up (censoring on aortic valve interventions). The secondary end point was overall mortality.

RESULTS

Rapid progressors accounted for 67 of the 229 patients (29%), and this feature was not associated with baseline characteristics. During a median of 5.8 years (interquartile range, 3.4-8.3 years) of follow-up from the first echocardiographic examination, 102 patients (45%) died, 86 (84%) during medical follow-up. Rapid progression rate predicted excess mortality (vs slow progression rate) after adjustment for age, sex, symptoms, baseline left ventricular ejection fraction, and baseline aortic valve area (hazard ratio, 2.50; 95% CI, 1.48-4.21; P = .0006) and after adjusting for peak aortic velocity and left ventricular ejection fraction obtained at the last echocardiographic examination (hazard ratio, 2.07; 95% CI, 1.25-3.46; P = .005). Among patients with baseline peak aortic velocity < 4 m/sec (nonsevere AS), rapid progression rate was associated with higher 5-year mortality compared with slow progression (57% vs 22% [P < .0001] under medical management and 44% vs 18% [P = .005] overall). Outcomes were comparable between nonsevere AS rapid progressors and baseline severe AS. Progression rate showed incremental prognostic value on receiver operating characteristic curve analysis versus AS severity. Of note, among slow progressors, 11 patients (5%) presented with high rates of symptom development and poor outcomes related to ventricular dysfunction or other advanced AS features.

CONCLUSIONS

Progression rate is an individual, almost unpredictable feature among patients with AS. Rapid progression is an incremental marker of excess mortality in asymptomatic patients with AS, independent of clinical and hemodynamic characteristics. Rapid progression rate may identify patients with nonsevere AS at higher risk for events.