Minimally Invasive Aortic Valve Replacement in Left Ventricular Dysfunction

The economic value of rapid deployment aortic valve replacement via full sternotomy

Aim: To compare the economic value of EDWARDS INTUITY Elite™ (EIE) valve system for rapid-deployment aortic valve replacement (RDAVR) in a full sternotomy (FS) approach (EIE-FS-RDAVR) versus FS-AVR using conventional stented bioprosthesis. Data & methods: A simulation model to compare each treatment's 30-day inpatient utilization and complication rates utilized: clinical end points obtained from the TRANSFORM trial patient subset (EIE-FS-RDAVR) and a best evidence review of the published literature (FS-AVR); and costs from the Premier database and published literature. Results: EIE-FS-RDAVR costs $800 less than FS-AVR per surgery episode attributable to lowered complication rates and utilization. Combined with the lower mortality, EIE-FS-RDAVR was a superior (dominant) technology versus FS-AVR. Conclusion: This preliminary investigation of EIE-FS-RDAVR versus conventional FS-AVR found the EIE valve offered superior economic value over a 30-day period. Real-world analyses with additional long-term follow-up are needed to evaluate if this result can be replicated over a longer timeframe.

Minimally invasive valve surgery in high-risk patients

The use of minimally, or less invasive, approaches to cardiac valve surgery has increased over the past decade. Because of its less traumatic nature, early studies in lower risk patients demonstrated the approach to be associated with an enhanced recovery, increased patient satisfaction, and good operative outcomes. With time, despite a steep learning curve, surgeons expanded this approach to perform more complex procedures, and include patients with more co-morbidity. The aim of this publication is to review the current literature involving the use of minimally invasive valve surgery (MIVS) in higher-risk patients.

Minimally invasive aortic valve replacement in high risk patient groups

Minimally invasive aortic valve replacement (AVR) aims to preserve the sternal integrity and improve postoperative outcomes. In low risk patients, this technique can be achieved with comparable mortality to the conventional approach and there is evidence of possible reduction in intensive care and hospital length of stay, transfusion requirement, renal dysfunction, improved respiratory function and increased patient satisfaction. In this review, we aim to asses if these benefits can be transferred to the high risk patient groups. We therefore, discuss the available evidence for the following high risk groups: elderly patients, re-operative surgery, poor lung function, pulmonary hypertension, obesity, concomitant procedures and high risk score cohorts.

Aortic valve replacement in patients with a left ventricular ejection fraction ≤35% performed via a minimally invasive right thoracotomy

BACKGROUND

We evaluated the outcomes of patients with aortic valve pathology in the setting of a left ventricular ejection fraction ≤35% who underwent minimally invasive aortic valve replacement (AVR), with or without concomitant mitral valve (MV) surgery.

METHODS

All minimally invasive AVR in patients with a left ventricular ejection fraction ≤35%, performed via a right thoracotomy for aortic stenosis or regurgitation between January 2009 and March 2013, were retrospectively evaluated. The operative characteristics, perioperative outcomes, and 30-day mortality were analyzed.

RESULTS

There were 75 patients identified: 51 who underwent isolated AVR, and 24 who had combined AVR plus MV surgery for moderate to severe mitral regurgitation. In patients undergoing MV surgery, there were 22 (91.7%) MV repairs [ring annuloplasty =7 (37.5%), transaortic edge-to-edge repair =15 (62.5%)], and 2 (8.3%) replacements. No patient required conversion to sternotomy for inadequate surgical field exposure. The median total mechanical ventilation time and intensive care unit length of stay were 14 (IQR, 8-20) and 42 hours (IQR, 26-93 hours) in the isolated AVR group, and 16.5 hours (IQR, 12-61.5 hours) and 95.5 hours (IQR, 43.5-159 hours) in the AVR plus MV surgery group, respectively. The most common post-operative complication was new-onset atrial fibrillation, which occurred in 15 (29.4%) isolated AVR and 4 (16.7%) AVR plus MV surgery patients. The median hospital length of stay and 30-day mortality was 7 days (IQR, 5-12 days) and 1 (2%) in the isolated AVR group, and 10.5 days (IQR, 5-21 days) and 1 (4.3%) for AVR plus MV surgery.

CONCLUSIONS

In patients with aortic valve pathology in the setting of a left ventricular ejection fraction ≤35%, minimally invasive AVR can be performed, with or without concomitant MV surgery, with a low morbidity and mortality.

Traditional Sternotomy Versus Minimally Invasive Aortic Valve Replacement in Patients Stratified by Ejection Fraction

OBJECTIVE

Low ejection fraction (EF < 40%) portends adverse outcomes in patients undergoing valvular heart surgery. The role of traditional median sternotomy aortic valve replacement (SAVR) compared with minimally invasive aortic valve replacement (MIAVR) in this cohort remains incompletely understood.

METHODS

A multi-institutional retrospective review of 1503 patients who underwent SAVR (n = 815) and MIAVR via right anterior thoracotomy (n = 688) from 2011 to 2014 was performed. Patients were stratified into two groups: EF of less than 40% and EF of 40% or more. In each EF group, SAVR and MIAVR patients were propensity matched by age, sex, body mass index, race, diabetes, hypertension, dyslipidemia, dialysis, cerebrovascular disease, cardiovascular disease, cerebrovascular accident, peripheral vascular disease, last creatinine level, EF, previous MI and cardiogenic shock, and the Society for Thoracic Surgeons (STS) score.

RESULTS

Among patients with an EF of 40% or more (377 pairs), patients who underwent MIAVR compared with SAVR had decreased intensive care unit hours (56.8% vs 84.6%, P < 0.001), postoperative length of stay (7.1 vs 7.9 days, P = 0.04), incidence of atrial fibrillation (18.8% vs 38.7%, P < 0.001), bleeding (0.8% vs 3.2%, P = 0.04), and a trend toward decreased 30-day mortality (0.3% vs 1.3%, P = 0.22). The STS scores were largely equivalent in patients undergoing MIAVR compared with SAVR (2.4% vs 2.6%, P = 0.09). In patients with an EF of less than 40% (35 pairs), there was no difference in intensive care unit hours (69% vs 72.6%, P = 0.80), postoperative length of stay (10.3 vs 7.2 days, P = 0.13), 30-day mortality (3.8% vs 0.8%, P = 0.50), or the STS score (3.3% vs 3.2%, P = 0.68).

CONCLUSIONS

Minimally invasive aortic valve replacement in patients with preserved EF was associated with improved short-term outcomes compared with SAVR. In patients with left ventricular dysfunction, short-term outcomes between MIAVR and SAVR are largely equivalent.

The economic value of INTUITY in aortic valve replacement

OBJECTIVE

The recent development of the EDWARDS INTUITY Elite™ (EIE) valve system enables the rapid deployment of a prosthetic surgical heart valve in an aortic valve replacement (AVR) procedure via both the minimally invasive (MISAVR) and conventional (CAVR) approaches. In order to understand its economic value, this study performed a cost evaluation of the EIE valve system used in a MIS rapid-deployment approach (MIS-RDAVR) vs MISAVR and CAVR, respectively, compared to standard prosthetic aortic valves.

METHODS

A simulation model was developed using TreeAge (and validated with MS Excel) to compare the inpatient utilization and complication costs for each treatment arm. Thirty-day clinical end-points for the MIS-RDAVR (mortality and complications) were taken from the TRANSFORM trial; and a best evidence review of the published literature was used for the MISAVR and CAVR approaches. Studies were pooled and parameter estimates were weighted by sample size in order to compare the TRANSFORM patients. Cost data (2016 USD) were taken from the Premier database. Incremental cost and cost-effectiveness was assessed and one-way/probabilistic sensitivity analyses performed to gauge the robustness of the results.

RESULTS

MIS-RDAVR costs $2,621 less than CAVR and had lower mortality rates, making it a superior (dominant) technology relative to CAVR. MIS-RDAVR costs $4,560 more than MISAVR, but was associated with an additional 0.20 life years-per-patient. This implies a cost-effectiveness ratio of $22,903 per-life-year-gained. Thus, MIS-RDAVR is cost-effective compared to MISAVR.

CONCLUSIONS

The EIE valve system deployed in a MIS approach appears to be a cost-effective technology compared to MISAVR and CAVR. When compared to CAVR it may achieve cost savings as well. These results suggest that MIS-RDAVR confers superior economic value compared to both standard MISAVR and CAVR via lowered key complication rates (re-operation, renal complications, wound infection, TIA, endocarditis) and utilization (cross-clamp time, hospital ward days).

Early outcomes after isolated aortic valve replacement with rapid deployment aortic valve

OBJECTIVE

Minimal access aortic valve replacement is associated with favorable clinical outcomes; however, several meta-analyses have reported significantly longer crossclamp times compared with a full sternotomy. We examined the procedural and early safety outcomes after isolated rapid deployment aortic valve replacement by surgical approach in patients enrolled in the Surgical Treatment of Aortic Stenosis With a Next Generation Surgical Aortic Valve trial.

METHODS

The Surgical Treatment of Aortic Stenosis With a Next Generation Surgical Aortic Valve trial was a prospective, multicenter, single-arm study, with successful implants in 287 patients with aortic valve stenosis who underwent rapid deployment aortic valve replacement using the EDWARDS INTUITY Valve System (Edwards Lifesciences, Irvine, Calif). Patients were evaluated perioperatively for procedural times and technical success rates; at discharge, for hospital length of stay; and, at 30 days, for early adverse events.

RESULTS

A total of 158 patients underwent isolated aortic valve replacement through a full sternotomy (n = 71), upper hemisternotomy (n = 77), or right anterior thoracotomy (n = 10). Mean age at baseline was 75.7 ± 7.2 years. Mean aortic crossclamp and cardiopulmonary bypass times (minutes) were similar for full sternotomy and upper hemisternotomy, 43.5 ± 32.5/71.6 ± 41.8 and 43.1 ± 13.1/69.6 ± 19.1, respectively, and significantly longer for right anterior thoracotomy, 88.3 ± 18.6/122.2 ± 22.1 (P < .000). Early adverse event rates were similar, and in-hospital mortality rates were low regardless of surgical approach.

CONCLUSIONS

These data suggest that isolated rapid deployment aortic valve replacement through an upper hemisternotomy can lead to shorter crossclamp times than has been reported historically in the literature. This may facilitate minimal access aortic valve replacement by eliminating the issue of prolonged crossclamp times. Further, low in-hospital mortality and new permanent pacemaker implant rates were observed regardless of surgical approach.

Minimally Invasive Aortic Valve Replacement

With the advent of transcatheter aortic valve replacement and the emergence of rapid deployment aortic valves, there is a resurgent interest in minimizing the trauma of surgical aortic valve replacement (AVR). The present review summarizes the history of minimal access AVR and attempts to collate the existing evidence regarding minimal access AVR.

Conventional versus minimally invasive aortic valve replacement: pooled analysis of propensity-matched data

BACKGROUND

Minimally invasive aortic valve replacement (mAVR) is increasingly preferred over conventional AVR (cAVR). However, data comparing these procedures present conflicting results. Hence, we conducted a systematic review and meta-analysis comparing clinical results in these cohorts.

METHOD

Only randomized controlled trials (RCT) and propensity-matched observational studies (POS) (1998-2013) comparing clinical outcome of patients subjected to mAVR or cAVR were pooled. Continuous data was compared using mean/standardized mean difference (MD/SMD) while categorical results were pooled to obtain an odds ratio (OR) with a 95% confidence interval.

RESULTS

A total of 18 studies (6 RCT and 12 POS) (1973 mAVR patients; 2697 cAVR patients) were analyzed. The mean ischemic time was significantly longer with mAVR (MD 9.42 minutes [4.25-14.59]; p < 0.01). However, early mortality (mAVR [1.8%] and cAVR [3%]) was comparable (OR 0.70 [0.46-1.06]; p = 0.09). Postoperative ventilation time was slightly shorter after mAVR (7.5 vs 11.1 hours; p = 0.07), and hospital discharge was earlier after mAVR (MD -1.05 [-1.64 to -0.46]; p < 0.01). However, mAVR failed to reduce transfusion requirement (OR 0.77 [0.51-1.14]; p = 0.19) or pain scores (SMD -0.25 [-0.65 to 0.13]; p = 0.20). Postoperative atrial fibrillation (p = 0.67) and stroke (p = 0.79) rates were comparable. Pooled rate of conversion to full sternotomy was 2.5%. Cosmetic satisfaction could not be pooled due to reporting heterogeneity.

CONCLUSION

Minimally invasive aortic valve replacement can be performed safely despite the longer ischemic time. While minimally invasive surgery does demonstrate some advantages in postoperative recovery, we failed to find any other substantial improvement in outcome over conventional aortic valve replacement.

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.

Ministernotomy or minithoracotomy for minimally invasive aortic valve replacement: a Bayesian network meta-analysis

BACKGROUND

Establishing the relative merits of ministernotomy (MS) and minithoracotomy (MT) approaches to minimally invasive aortic valve replacement (MIAVR) is difficult given the limited available direct evidence. Network meta-analysis is a Bayesian approach that can combine direct and indirect evidence to better define the benefits and risks of MS and MT.

METHODS

Electronic searches were performed using six databases from their inception to June 2014. Relevant studies utilizing a minimally invasive approach for aortic valve replacement were identified. Data were extracted and analyzed according to predefined clinical endpoints. Both traditional and Bayesian meta-analysis approaches were conducted.

RESULTS

Compared to full sternotomy, MT was associated with longer cardiopulmonary bypass (CPB) duration (WMD, 9.99; 95% CI, 3.91, 16.07; I(2)=55%; P=0.001) and cross-clamp duration (WMD, 7.64; 95% CI, 2.86, 12.42; P=0.002; I(2)=74%). When compared to MS using network meta-analysis, no significant difference in duration was detected. Postoperative outcomes including 30-day mortality, stroke, and reoperation for bleeding and wound infection were comparable between MS and MT using both traditional and Bayesian meta-analysis techniques.

CONCLUSIONS

The current evidence demonstrates that MIAVR via MS or MT is a safe and efficacious alternative to conventional median sternotomy. MT may be associated with longer CPB and cross-clamp durations, but has similar post-operative outcomes compared to MS. An individualized approach tailored to both the patient and surgical team is likely to provide optimal outcomes.

Aortic valve replacement surgery: comparison of outcomes in matched sternotomy and PORT ACCESS groups

BACKGROUND

In the past decade, minimally invasive approaches have been developed for aortic valve surgery. We reviewed our data to determine if the use of the PORT ACCESS technique has improved hospital morbidity and mortality.

METHODS

Data were collected on 90 patients who had a replacement of their aortic valve using PORT ACCESS procedures (PORT ACCESS aortic valve replacement [PAVR]). This group was then matched 1:4 to a control group having aortic valve replacement surgery using a standard sternotomy approach.

RESULTS

The two groups had no statistically significant differences in preoperative risk factors. The perioperative and 30-day outcomes from the matched AVR and PAVR groups showed no mortalities in the PAVR group and 3.1% in the AVR group. Mean length of stay was shorter for PAVR patients (7.2 +/- 5.0 days; median 6 days) compared with the mean stay in the sternotomy group (8.5 +/- 9.5 days; median 6 days), PAVR patients also had statistically significant shorter intensive care unit stays, and time on ventilator. The number of patients needing ventilator support postoperatively was significantly lower in the PORT ACCESS group. Cross-clamp and perfusion times were longer in the PAVR group. No other morbidity was significantly different between groups, except for postoperative tamponade (higher in PAVR group).

CONCLUSIONS

In this analysis of matched patients, the patients having aortic valve replacement using PORT ACCESS procedures, spent a shorter time in the intensive care unit and had less need for postoperative ventilator usage (both number of patients using a ventilator and the mean time of use) in comparison with patients undergoing conventional sternotomy.