Current approaches to minimally invasive aortic valve surgery

Initial clinical experience with minimally invasive surgical aortic valve replacement

BACKGROUND

The ministernotomy approach is increasingly used in aortic valve surgery. However, the advantages are still a matter of discussion. The aim of this study was to compare the postoperative outcome in patients undergoing elective aortic valve operation, either through mini-sternotomy or conventional sternotomy.

METHODS

We included 317 patients who were treated for their aortic valve, 63 patients underwent a minimally invasive aortic valve replacement (mini-AVR) and 254 patients underwent a full-sternotomy AVR. Patients with endocarditis, those who underwent previous cardiac surgery and those who required a concomitant procedure were excluded from the analysis. The method of matching weights according to propensity score was used to adjust for differences between the two treatment groups, and outcomes were compared.

RESULTS

The mediastinal drainage was significantly lower at 6, 24 hours and total after mini-AVR procedure than after full-sternotomy AVR (median: 373 vs. 499 mL, P<0.001). However, the number of patients receiving packed red blood cells transfusion was similar. Overall, the hospital mortality was lower in the full-sternotomy group, 0% vs. 3.2%, P=0.039. No difference was found in the median hospital length of stay, perioperative myocardial infarction, postoperative incidence of new pacemaker implantation, stroke, prolonged mechanical ventilation and mediastinitis. No patients in the mini-AVR group experienced paravalvular leakage. Midterm survival resulted in no difference between the treatment groups at 4-year (90.5% vs. 95.2%), P=0.75.

CONCLUSIONS

Although the minimally invasive surgery for AVR may increasingly be applied, our initial experience calls for a careful approach of adapting this procedure.

Aortic valve replacement via right minithoracotomy versus median sternotomy: a propensity score analysis

OBJECTIVE

The aim of this study was to define the relative role of a right minithoracotomy (RT) versus standard median sternotomy (ST) for open aortic valve replacement (AVR).

METHODS

A retrospective analysis was performed of all 1348 patients undergoing isolated, open AVR at a single institution during a 14-year period. Because relatively few patients were technically suitable for redo AVR with the RT approach (n = 20), all redo patients (n = 209) were excluded, leaving 1139 patients available for analysis. Patients converting from RT to ST approach (n = 15) were analyzed separately.

RESULTS

Relative to ST (n = 672), the RT patients (n = 452) were older with more stenosis but with more recent operation year, lower rate of congestive heart failure, higher ejection fraction, lower rate of endocarditis, and lower rate of renal disease than the ST AVR patients (all P < 0.0001). Right minithoracotomy AVR was associated with longer cardiopulmonary bypass times [157 (25) vs 131 (38), P = 0.0004] and clamp times [103 (20) vs 85 (27), P < 0.0001] but less transfusion (1.4 vs 3.4 U, P = 0.0003), less chest tube output (405 vs 950 mL, P < 0.0001), fewer reoperations for bleeding (0.4% vs 4%, P < 0.0001), shorter length of stay (6 vs 8 days, P = 0.03), and lower rate of atrial fibrillation (15% vs 20%, P = 0.03). Stroke, operative mortality, and survival were not significantly different between the groups.

CONCLUSIONS

Given the biases of retrospective propensity-adjusted analysis, these data suggest that RT AVR is a safe alternative to ST AVR in selected patients, with advantages of avoiding sternotomy with associated bleeding, transfusion, and delayed wound healing, at the expense of longer pump and clamp times.

Minimally invasive valve surgery

Cardiac valve surgery is life saving for many patients. The advent of minimally invasive surgical techniques has historically allowed for improvement in both postoperative convalescence and important clinical outcomes. The development of minimally invasive cardiac valve repair and replacement surgery over the past decade is poised to revolutionize the care of cardiac valve patients. Here, we present a review of the history and current trends in minimally invasive aortic and mitral valve repair and replacement, including the development of sutureless bioprosthetic valves.

The golden age of minimally invasive cardiothoracic surgery: current and future perspectives

Over the past decade, minimally invasive cardiothoracic surgery (MICS) has grown in popularity. This growth has been driven, in part, by a desire to translate many of the observed benefits of minimal access surgery, such as decreased pain and reduced surgical trauma, to the cardiac surgical arena. Initial enthusiasm for MICS was tempered by concerns over reduced surgical exposure in highly complex operations and the potential for prolonged operative times and patient safety. With innovations in perfusion techniques, refinement of transthoracic echocardiography and the development of specialized surgical instruments and robotic technology, cardiac surgery was provided with the necessary tools to progress to less invasive approaches. However, much of the early literature on MICS focused on technical reports or small case series. The safety and feasibility of MICS have been demonstrated, yet questions remain regarding the relative efficacy of MICS over traditional sternotomy approaches. Recently, there has been a growth in the body of published literature on MICS long-term outcomes, with most reports suggesting that major cardiac operations that have traditionally been performed through a median sternotomy can be performed through a variety of minimally invasive approaches with equivalent safety and durability. In this article, we examine the technological advancements that have made MICS possible and provide an update on the major areas of cardiac surgery where MICS has demonstrated the most growth, with consideration of current and future directions.

Outcomes of a minimally invasive approach compared with median sternotomy for the excision of benign cardiac masses

BACKGROUND

We hypothesize that for the excision of benign cardiac masses, a minimally invasive approach through a right minithoracotomy is safe and feasible, and has lower resource utilization when compared with a standard median sternotomy.

METHODS

We retrospectively analyzed 39 consecutive patients who underwent benign cardiac mass excision at our institution between December 1999 and April 2010. The in-hospital outcomes of patients who had a right minithoracotomy were compared with those of patients who underwent a standard median sternotomy.

RESULTS

Of the 39 patients, 22 had cardiac masses removed through a minimally invasive approach, and 17 had a median sternotomy. The type of masses resected included 26 myxomas (66.7%), 9 papillary fibroelastomas (23.1%), and 4 thrombi (10.2%). The aortic cross-clamp and cardiopulmonary bypass times were 43 minutes (interquartile range [IQR] 30 to 64) versus 31 minutes (IQR 23 to 47; p=0.20) and 78 minutes (IQR 55 to 88) versus 57 minutes (IQR 33 to 70; p=0.02) for the minimally invasive group and the median sternotomy group, respectively. There were no significant differences in postoperative complications including mortality. The mean intensive care unit and hospital lengths of stay were 27 hours (IQR 24 to 47) versus 60 hours (IQR 48 to 79; p=0.001) and 5 days (IQR 4 to 6) versus 7 days (IQR 6 to 8; p=0.03) for the minimally invasive and the median sternotomy group, respectively.

CONCLUSIONS

A minimally invasive approach through a right minithoracotomy for the resection of benign cardiac masses can be performed safely with lower resource utilization, and should be considered for these patients.

Outcomes of minimally invasive valve surgery versus median sternotomy in patients age 75 years or greater

BACKGROUND

Advanced age is a major predictor of poor outcome in patients undergoing valve surgery. We hypothesized that elderly patients who underwent minimally invasive valve surgery for aortic or mitral valve disease would do better when compared with those undergoing the standard median sternotomy.

METHODS

We retrospectively reviewed 2,107 consecutive heart operations at our institution and identified 203 patients, age 75 years or greater, who underwent isolated mitral or aortic valve surgery. Outcomes of those who had minimally invasive valve surgery through a right minithoracotomy were compared with those who had a median sternotomy.

RESULTS

Of the 203 patients, 119 (59%) underwent a minimally invasive approach, while 84 (41%) had a median sternotomy. The median postoperative length of stay was 7 days (interquartile range [IQR] 6 to 10) versus 12 days (IQR 9 to 20), p less than 0.001, and intensive care unit length of stay was 52 hours (IQR 44 to 93) versus 119 hours (IQR 57 to 193), p less than 0.001 for minimally invasive and median sternotomy, respectively. In-hospital mortality was 2 (1.7%) versus 8 (9.5%, p=0.01 and composite postoperative morbidity and mortality occurred in 25 (21%) versus 38 (45.2%), p less than 0.001, in minimally invasive versus median sternotomy, respectively. The difference was driven by the following: a lower incidence of acute renal failure, 1 (0.8%) versus 14 (16.7%), p<0.001; prolonged intubation 23 (19.3%) versus 32 (38.1%), p=0.003; wound infections 1 (0.8%) versus 5 (6%), p=0.034; and death.

CONCLUSIONS

Minimally invasive surgery for isolated valve lesions in elderly patients yields a lower morbidity and mortality when compared with median sternotomy and should be considered when such individuals require valve surgery.