Minimally invasive aortic valve replacement

Abstract

Background: Minimally invasive aortic valve replacement (AVR) through a ministernotomy has been developed as an alternative approach to conventional full sternotomy AVR. During recent years, sutureless aortic bioprostheses were introduced with the aim to facilitate implantation, especially in minimally invasive procedures. The aim of this thesis was to evaluate minimally invasive and sutureless AVR on the aspects of clinical outcomes, cardiac function, and prosthetic valve function.

Methods and Results: Study I. Early postoperative outcomes and 2-year survival after isolated AVR with the Perceval sutureless bioprosthetic valve (LivaNova, Milan, Italy) performed through ministernotomy compared with full sternotomy was investigated. Of 267 patients, 189 (70.8%) were performed through ministernotomy and 78 through full sternotomy. Aortic cross-clamp (44 minutes in both groups) and cardiopulmonary bypass time (69 vs. 74 minutes, p=0.363) did not differ between the groups after propensity score matching. Apart from slightly higher postoperative transvalvular gradients in the ministernotomy group, early postoperative outcomes did not differ. There were no differences regarding in-hospital mortality rate or 2-year survival between the groups.

Study II. Early postoperative outcomes and 2-year survival after isolated AVR through ministernotomy with implantation of a sutureless bioprosthesis compared with full sternotomy with implantation of a stented bioprosthesis was studied. Of 565 patients, 182 (32%) underwent ministernotomy with a sutureless bioprosthesis and 383 full sternotomy with a stented bioprosthesis. Aortic cross-clamp (40 vs. 65 min, p<0.001) and cardiopulmonary bypass time (69 vs. 87 min, p<0.001) were shorter in the ministernotomy sutureless group after propensity score matching. Patients undergoing ministernotomy received less packed red blood cells but the risk for postoperative permanent pacemaker implantation was higher. There were no differences regarding 30-day mortality or 2-year survival between the two groups.

Study III. Right ventricular function after AVR was investigated in forty patients undergoing primary isolated AVR randomized to ministernotomy or full sternotomy. Four days postoperatively, tricuspid annular plane systolic excursion had decreased in both the ministernotomy and the sternotomy group (ministernotomy: 25 vs. 16 mm, p<0.001; sternotomy: 22.5 vs. 8 mm, p<0.001) but was higher in the ministernotomy group (p<0.001). Pulsed wave tissue Doppler right ventricular velocity decreased significantly in patients who underwent sternotomy (10.5 vs. 6.5 cm/s, p<0.001) but did not decrease significantly in patients who underwent ministernotomy (11.5 cm/s vs. 10 cm/s, p=0.054). Right ventricular fractional area change was equally decreased in both groups (ministernotomy: 46 vs. 38 %, p<0.001; sternotomy: 45 vs. 37 %, p=0.003). The differences between the groups were similar 40 days postoperatively.

Study IV. Hypo-attenuated leaflet thickening (HALT) and reduced leaflet motion (RLM) assessed with cardiac computed tomography were studied in 47 patients who underwent AVR and received a Perceval sutureless bioprosthetic valve. Also, the relation between HALT and RLM and the influence of anticoagulation treatment on HALT and RLM were investigated. Hypo-attenuated leaflet thickening was found in 18 (38%) patients and RLM in 13 (28%) patients. All patients with RLM had HALT. Both HALT and RLM was found in patients with ongoing anticoagulation treatment. Hypo-attenuated leaflet thickening and RLM were not associated with clinical symptoms.

Conclusions: [1] AVR with implantation of the Perceval sutureless bioprosthetic valve through a ministernotomy was a safe procedure with early postoperative outcomes and 2-year survival comparable to full sternotomy AVR. Procedural times were not prolonged in patients undergoing ministernotomy compared to patients undergoing full sternotomy. [2] AVR through a ministernotomy with implantation of a sutureless bioprosthetic valve was associated with shorter procedural times and less transfusion of packed red blood cells, but a higher risk for permanent pacemaker implantation compared with a full sternotomy with implantation of a stented bioprosthesis. [3] Right ventricular long axis function was reduced after both ministernotomy and full sternotomy aortic valve replacement, but the reduction was more pronounced in the full sternotomy group. Global right ventricular function was equally impaired after ministernotomy and full sternotomy AVR. [4] Hypo-attenuated leaflet thickening and RLM were prevalent in the Perceval sutureless bioprosthetic valve. Both HALT and RLM was found in patients with ongoing anticoagulation treatment.