A water-test is performed to assess the coaptation of the reimplanted native AV. Additional AV leaflet repair is performed if needed. The coronary buttons are reinserted using a continuous 5-0 polypropylene suture. Finally, the valve and hemostasis are tested by pressurizing the aortic root with cardioplegia. Meticulous hemostasis is particularly important factor during minimally invasive David procedure.
The distal anastomosis is performed, and the aortic clamp removed after de-airing. AV function is assessed by intraoperative TOE. Patients require long-life antiplatelet therapy with aspirin. Repeat transthoracic echocardiography is recommended before discharge.
Postoperative management and outcomes
Patients undergoing minimally invasive David procedure require special postoperative management in order to achieve faster recovery as expected after minimally invasive surgery. Immediate perioperative anesthetic management individualized to each patient and early extubation represent important adjuncts in the early postoperative care of these patients. Complete rewarming of the patient is achieved while in the operating room. In the event of significant bleeding, re-exploration should be accomplished through the same incision.
Recent studies reported postoperative clinical outcomes with minimally invasive David procedure comparable to the conventional technique.10-16 Postoperative outcomes and characteristics of included studies are demonstrated in a Table 1. 30-day mortality was reported between 0% and 3.3%, although all the published series had a sample size of less than 100 patients.10-16 Furthermore, selection of patients might have positively influenced outcomes as minimal access was performed in elective patients with noncalcified aortic valves. Notably, Marfan syndrome was reported in 3.9-18.8% of patients and they represent a subgroup of patients that could benefit most of minimal access technique.10-16
Aortic cross clamp and CPB time were somewhat longer than in standard David procedure and ranged from 111 to 168.5 minutes and from 139 to 199.5 minutes, respectively.10-16 However, it seems that this has not negatively influenced postoperative clinical outcomes. Several studies reported decreased requirements for blood products, relatively shorter ICU length of stay (1.1-3 days) and low 30-day stroke rate (0-3.3%). Despite the fact that most centers emphasized importance of meticulous hemostasis, re-exploration for bleeding was reported up to 9% in some of the studies.10,11,13
In summary, our review of available literature on the topic of minimally invasive David procedure demonstrated that this approach could facilitate recovery of selected elective patients with isolated aortic root aneurysm along with similar early postoperative outcomes to conventional surgery. However, there are many potential pitfalls in minimally invasive David procedure and recent studies highlighted challenges of the learning curve. Sufficient experience at centers with adequate case volumes in both conventional aortic root surgery and minimal access AVR are necessary before progressing to the next step to avoid potential vulnerability and performance obstacles.
Ljubljana experience
At the University Hospital Center Ljubljana (Slovenia, EU), 16 patients (12 male) with isolated aortic root aneurysm were selected for minimally invasive David procedure over a 4-year period (Figure 1). No Ethics Committee approval was required given that this analysis was retrospective and anonymized. All patients were consented for the surgery and use of their anonymized data for future research and publications.
Concomitant aortic valve repair was performed in 8 out of 16 (50%) patients and coronary artery bypass graft (saphenous venous graft to right coronary artery) in one patient. In most cases, straight 30-32 mm Dacron graft (Gelweave) was used. Technique was also modified by performing wrapping of distal anastomosis in 10 out of 16 patients as, in our experience, it was helpful in achieving better hemostasis. No conversion to full sternotomy or re-exploration due to bleeding was observed. 30-day postoperative mortality and stroke were 0%.