Comparison of transprosthetic mean pressure gradients between Medtronic Hall and ATS valves in the aortic position

Aortic valve replacement in small aortic root- Bi-leaflet mechanical valve is superior to a Mono-leaflet mechanical valve

Background

Patient prosthetic mismatch is a serious but avoidable complication of surgical aortic valve replacement (SAVR) complicated by a small aortic annulus. This study aims to compare early and midterm outcomes following aortic valve replacement (AVR) with a mono-leaflet (ML) valve and a bi-leaflet (BL) valve in a small aortic root.

Methods and selection

From January 1st, 2017 to December 31st, 2019, 98 patients diagnosed with small aortic root underwent isolated aortic valve replacement with either TTK Chitra valve (Mono-leaflet/ ML group) or St. Jude medical valve (Bi-leaflet/ BL group) of size 17/ 19 mm. Echocardiography was analyzed from medical records and telephonic follow-up.

Results

Baseline parameters were comparable. The ML group had 42 patients and the BL group had 56 patients. Aortic cross-clamp time, the incidence of severe patient prosthetic mismatch (p = 0.002) and mean, peak pressure gradients were high in the ML group. Duration of ventilation, intensive care unit (ICU) stay, the incidence of stroke, need for intra-aortic balloon pump, permanent pacemaker, dialysis, and left ventricular mass index in echocardiography were comparable between the two groups postoperatively. There was no early mortality in both group. Survival at the end of 5 years was 57 ± 14.4% in the ML group; 91.8 ± 4% in the BL group (p = 0.005). Univariate and multivariate analysis revealed elderly age as a risk factor for mortality.

Conclusion

We conclude that aortic valve replacement without any root widening procedure, using a small-sized mechanical valve provides acceptable early outcomes. Bi-leaflet mechanical valves provide better hemodynamics and survival percentage.

Late clinical outcomes after mechanical aortic valve replacement for aortic stenosis: old versus new prostheses

Background

The study aimed to evaluate the late clinical outcomes of new-generation mechanical valves for severe aortic stenosis (AS) compared with old mechanical valves.

Methods

We retrospectively reviewed data from 254 patients with severe AS, who underwent primary mechanical aortic valve replacement from 1995 to 2013. Patients were classified into two groups: old-valve group (n=65: 33 ATS standard, 32 Medtronic-Hall) and new-valve group (n=189: 113 St. Jude Regent, 46 On-X, 30 Sorin Overline). Median patient age was 58 years (Q1-Q3: 52-61). With propensity score matching based on demographic information, 56 patients in the old-valve group were matched with 177 patients in the new-valve group. The median follow-up duration was 91 months (Q1-Q3: 48-138).

Results

Cardiac-related mortality and hemorrhagic events were significantly lower in the new-valve group (P=0.047 and P=0.032, respectively). The median international normalized ratio (INR) at follow-up was significantly higher in the old-valve group [2.23, Q1-Q3: 2.14-2.35 (old-valve group); 2.08, Q1-Q3: 1.92-2.23 (new-valve group), P<0.001]. The incidence of prosthesis-patient mismatch (PPM) was significantly higher in the old-valve group (P<0.001). Multivariate analysis of the total population revealed that PPM was a significant risk factor for cardiac-related events [hazard ratio (HR) =5.279, 95% CI, 1.886-14.561, P=0.002] and showed higher trend of increasing mortality (HR =3.082, P=0.076).

Conclusions

New mechanical prostheses showed a better hemodynamic performance and lower incidence of PPM. Anticoagulation strategy to lower the target INR in patients with new mechanical valves may improve late outcomes by reducing hemorrhagic events.

Twenty-Five–Year Experience With the Medtronic-Hall Valve Prosthesis in the Aortic Position

Background— The Medtronic-Hall valve was developed and for the first time implanted in Oslo, Norway, in 1977. A total of 1104 patients received this valve at Rikshospitalet from 1977 to 1987. In the present study, we followed up on all 816 patients undergoing aortic valve replacement over a 25-year period.

Methods and Results— This is a retrospective cohort analysis of 816 consecutive patients undergoing aortic valve replacement with the Medtronic-Hall valve at Rikshospitalet, Oslo, Norway, from 1977 to 1987. All patients were contacted by means of questionnaires or telephone. Data were checked against hospital databases and medical records. Date of death was verified by the Norwegian civil registry. Follow-up was 99.6% complete. Survival analysis included operative deaths as well as late deaths. Survival at 25 years was 24.9%. No mechanical failures were found. Valve thrombosis was seen in 4 patients, in 1 case combined with pannus formation. Small valves (20 mm to 21 mm) were associated with reduced survival; however, when controlled for the confounding effects of age and gender, valve size did not remain a significant risk factor. Patient-related factors were important: Older age, female gender, and the need for concomitant coronary artery bypass surgery significantly reduced survival, whereas surgery of the ascending aorta did not. Linearized rates of thromboembolic complications, warfarin-related bleeding, and endocarditis were 1.5%, 0.7%, and 0.16%/patient-year, respectively. At follow-up, 79% of the patients were in New York Heart Association classes I to II.

Conclusions— This study confirms the excellent long-term outcome for patients with Medtronic-Hall valves in the aortic position.