Prosthetic aortic heart valves

Abstract

Background: Aortic valve replacement (AVR) can be performed with different types of valve prostheses. There is no perfect aortic valve prosthesis, and the prosthetic choice for each patient requires careful consideration. This thesis evaluates mortality, morbidity, and prosthetic valve function after AVR with different aortic valve prostheses.

Methods and Results: Study I: We studied all-cause mortality and postoperative outcomes in all 1219 patients who underwent AVR at Karolinska University Hospital between 2002 and 2010 and received either Perimount (n=864; Edwards Lifesciences, Irvine, CA) or Mosaic (n=355; Medtronic, Inc., Minneapolis, MN) bioprostheses. There was no difference in all-cause mortality (adjusted hazard ratio (HR) 0.85, 95% confidence interval (CI) 0.65–1.11) or rate of aortic valve reoperation between the two groups. Severe prosthesis–patient mismatch (PPM) was more common in the Mosaic group than in the Perimount group (15% vs. 6%, p<0.001).

Study II: We studied hemodynamic function and postoperative outcomes in all 355 patients who underwent AVR at Karolinska University Hospital between 2002 and 2008 and received a Mosaic bioprosthesis. The mean pressure gradient was 21.2 mmHg and 22.5 mmHg during early and late echocardiography, respectively. Moderate or severe PPM was found in 299 (84%) patients, and 46 patients had moderate or severe aortic stenosis at late echocardiography, but neither was associated with increased mortality.

Study III: We studied all-cause mortality and postoperative outcomes in all 4545 patients aged 50–69 years who underwent primary, isolated AVR with biological (n=1832) or mechanical (n=2713) prostheses in Sweden between 1997 and 2013. The study population was obtained from the SWEDEHEART register. In a propensity score-matched analysis, patients with mechanical valve prostheses had better survival than patients with bioprostheses (HR 1.34, 95% CI 1.09–1.66, p=0.006). There was no difference in the rate of stroke, but patients with mechanical valves had a higher risk of major bleeding events and a lower risk of aortic valve reoperation than patients with bioprostheses.

Study IV: We studied all-cause mortality and postoperative outcomes in all 13 102 patients with moderately reduced (n=3266), or normal (n=9836) kidney function who underwent primary AVR in Sweden between 1997 and 2013. The study population was obtained from the SWEDEHEART register. Patients with normal kidney function had better survival than patients with moderately reduced kidney function (adjusted HR 1.28, 95% CI 1.18–1.38). Patients with moderately reduced kidney function had a slightly higher risk of major bleeding events and a lower risk of aortic valve reoperation than patients with normal kidney function.

Study V :We studied the incidence of prosthetic valve endocarditis (PVE) in all 26 580 patients who underwent AVR with biological (n=16 426) or mechanical (n=10 154) prostheses in Sweden between 1995 and 2012. The study population was obtained from the SWEDEHEART register. The incidence rate of PVE was 0.57% (95% CI 0.54–0.61) per person-year. The incidence of PVE was highest during the first year after surgery and remained stable thereafter for up to 18 years of follow-up. The risk of PVE was higher in patients with bioprostheses than in patients with mechanical valve prostheses (adjusted HR 1.54, 95% CI 1.29–1.83, p<0.001).

Study VI: We performed a systematic review and meta-analysis evaluating all-cause mortality after AVR in 49 190 patients who received bovine (n=32 235) versus porcine (n=16 955) bioprostheses. In total, seven articles met the inclusion criteria. The random-effects model was used to obtain pooled HR and 95% CI. The meta-analysis revealed no difference in survival between the groups (pooled HR 1.00, 95% CI 0.92–1.09).

Conclusions: [1] Both the Perimount and Mosaic bioprostheses are acceptable valve alternatives for AVR. [2] In patients aged 50–69 years, survival after AVR was better for those who received mechanical valve prostheses rather than bioprostheses. [3] After AVR, patients with moderately reduced kidney function have higher mortality than patients with normal kidney function. [4] After AVR, the yearly rate of PVE was 0.57%. Patients with bioprostheses had a higher risk of PVE than that of patients with mechanical valves. [5] Both bovine and porcine bioprostheses are acceptable valve choices for AVR.