Minimally invasive aortic valve replacement: how does this perform in high-risk patients?

Minimally invasive approaches versus conventional sternotomy for aortic valve replacement in patients with aortic valve disease: a systematic review and meta-analysis of 17 269 patients

Background

Aortic valve replacement (AVR) is a common procedure for aortic valve pathologies, particularly in the elderly. While traditional open AVR is established, minimally invasive techniques aim to reduce morbidity and enhance treatment outcomes. The authors' meta-analysis compares these approaches with conventional sternotomy, offering insights into short and long-term mortality and postoperative results. This study provides valuable evidence for informed decision-making between conventional and minimally invasive approaches for AVR.

Materials and methods

Till August 2023, PubMed, Embase, and MEDLINE databases were searched for randomized controlled trials (RCT) and propensity score matched (PSM) studies comparing minimally invasive approaches [mini-sternotomy (MS) and right mini-thoracotomy (RMT)] with full sternotomy (FS) for AVR. Various outcomes were analyzed, including mortality rates, bypass and clamp times, length of hospital stay, and complications. Risk ratios (RR) and the weighted mean differences (WMD) with corresponding 95% CIs were calculated using Review Manager.

Results

Forty-eight studies were included having 17 269 patients in total. When compared to FS, there was no statistically significant difference in in-hospital mortality in MS (RR:0.80; 95% CI:0.50-1.27; I2=1%; P=0.42) and RMT (RR:0.70; 95% CI:0.36-1.35; I2=0%; P=0.29). FS was also linked with considerably longer cardiopulmonary bypass duration than MS (MD:8.68; 95% CI:5.81-11.56; I2=92%; P=0.00001). The hospital length of stay was determined to be shorter in MS (MD:-0.58; 95% CI:-1.08 to -0.09; I2=89%; P=0.02) with no statistically significant difference in RMT (MD:-0.67; 95% CI:-1.42 to 0.08; I2=84%; P=0.08) when compared to FS.

Conclusions

While mortality rates were comparable in minimally invasive approaches and FS, analysis shows that MS, due to fewer respiratory and renal insufficiencies, as well as shorter hospital and ICU stay, may be a safer approach than both RMT and FS.

Low-Risk Surgical Aortic Valve Replacement in the Era of Transcatheter Aortic Valve Implantation

Open surgical aortic valve replacement (SAVR) is a viable alternative to transcatheter implantation in low-risk patients. In this light, we evaluated the safety and effectiveness of SAVR performed through conventional and less invasive surgical approaches in a high-volume center.

We retrospectively reviewed the records of 395 consecutive patients who underwent open SAVR from January 2019 through December 2019 in our center. We evaluated and compared the operative results and postoperative major adverse outcomes of 3 surgical approaches: full median sternotomy (n=267), upper ministernotomy (ministernotomy) (n=106), and right anterior thoracotomy (minithoracotomy) (n=22).

Overall, the 30-day all-cause mortality rate was 0.8% (3 patients). Stroke occurred in 8 patients (2%), disabling stroke in 4 patients (1%), myocardial infarction in 1 (0.2%), and surgical site infection in 13 (3.2%). There was no difference in 30-day mortality rate or incidence of postoperative major adverse events among the 3 surgical groups. Stroke and surgical site infection occurred more frequently, but not significantly so, in the full-sternotomy group. The mean hospital stay was longer after full sternotomy (9.1 ± 5.5 d) than after ministernotomy (7.5 ± 2.9 d) or minithoracotomy (7.4 ± 1.9 d) (P=0.012).

Our findings suggest that open SAVR performed in a high-volume center is associated with a low early mortality rate and that less invasive approaches result in faster postoperative recovery and shorter hospital stays.

Fabrication and in-vitro characterization of a polymeric aortic valve for minimally invasive valve replacement

The valve replacement therapy is the standard treatment for severe heart valve diseases. Nowadays, two types of commercial prosthesis are available: mechanical and biological, but both of them have severe limitations. Moreover, alternative therapeutic approach for valve replacement, based on minimally invasive techniques (MIAVR), motivates the search for new valve materials. In this study a polyurethane-based self-expandable tri-leaflets heart valve compatible with MIAVR procedure is proposed. The device is based on the development, fabrication and characterization of three different elements: the leaflets, the polymeric stent for supporting the leaflets, and the external metallic stent for anchoring the valve to the native aortic root. The polymeric stent and the valve leaflets were fabricated using a thermoplastic silicone-polycarbonate-urethane using 3D printing and spray technology while the external metallic stent was made in nickel titanium (Nitinol) to obtain a self-expandable valve after the crimping process. The three elements were assembled in the completed device and tested by crimping, fatigue and fluid-dynamic test. The novel polymeric valve proposed showed promising results about valve crimping capabilities, durability and fluid dynamic performances. This approach could offer advantages such as low cost and to produce a tailor-made device basing on patient's imaging data. Moreover, the selected biomaterial offers the potential to have a device that could need of permanent anticoagulation and lack of calcification.

Right anterior mini-thoracotomy and sutureless valves: the perfect marriage

Background

A minimally invasive approach (MIA) reduces mortality and morbidity in patients referred for aortic valve replacement (AVR). Sutureless technology facilitates a MIA. We describe our experience with the sutureless Perceval (LivaNova, Italy) aortic bioprosthesis through a right anterior mini-thoracotomy (RAMT) approach.

Methods

Between March 2011 and October 2019, 1,049 patients underwent AVR with Perceval bioprosthesis. Five hundred and three patients (48%) were operated through a RAMT approach in the second intercostal space. Considering only isolated AVR (881), 98% of patients were operated with MIA, and Perceval in RAMT approach was performed in 57% of these patients. Eight patients (1.6%) had previously undergone cardiac surgery. The prosthesis sizes implanted were: S (n=91), M (n=154), L (n=218) and XL (n=40). Concomitant procedures were mitral valve surgery (n=6), tricuspid valve repair (n=1), mitral valve repair and tricuspid valve repair (n=1) and miectomy (n=2). Mean age was 78±4 years (range, 65-89 years), 317 patients were female (63%) and EuroSCORE II was 5.9%±8.4%.

Results

The 30-day mortality was 0.8% (4/503). Cardiopulmonary bypass (CPB) and aortic cross-clamp times were 81.6±30.8 and 50.3±24.5 minutes respectively for stand-alone procedures. In two patients, early moderate paravalvular leakage appeared as a result of incomplete expansion of the sutureless valve due to oversizing of the bioprosthesis, requiring reoperations at two and nine postoperative days with sutured aortic bioprosthesis implantation. Permanent pacemaker implantation within the first thirty days was necessary in 26 (5.2%) patients. At the mean follow-up of 4.6 years (range, 1 month to 8.6 years), survival was 96%, freedom from reoperation was 99.2%, and mean transvalvular pressure gradient was 11.9±4.3 mmHg.

Conclusions

AVR with the Perceval bioprosthesis in a RAMT approach is a safe and feasible procedure associated with low mortality and excellent hemodynamic performance. Sutureless technology facilitates a RAMT approach.

[Right thoracotomy approach for minimally invasive mitral valve surgery]

Minimally invasive approach in mitral valve surgery has been applied since the late 1990s. Considerable experience of mini-thoracotomy in cardiac surgery has been gained over this period. Stages of the development of minimally invasive cardiac surgery are reviewed in the article. Features of mitral valve surgery through right-sided mini-thoracotomy are discussed. Surgical outcomes of these procedures are reported considering data of various cardiac surgery centers. Moreover, the authors determined indications and limitations of this technique.

Improved operative and recovery times with mini-thoracotomy aortic valve replacement

Background

The small incisions of minimally invasive surgery have the proposed benefit of less surgical trauma, less pain, and faster recovery. This study was done to compare minimally invasive techniques for aortic valve replacement, including right anterior mini-thoracotomy and mini-sternotomy, to conventional sternotomy.

Methods

We retrospectively reviewed 503 patients who underwent isolated aortic valve replacement at our institution from 2012 to 2015 using one of three techniques: 1) Mini-thoracotomy, 2) Mini-sternotomy, 3) Conventional sternotomy. Demographics, operative morbidity, mortality, and postoperative complications were compared.

Results

Of the 503 cases, 267 (53.1%) were mini-thoracotomy, 120 (23.8%) were mini-sternotomy, and 116 (23.1%) were conventional sternotomy. Mini-thoracotomy patients, compared to mini-sternotomy and conventional sternotomy, had significantly shorter bypass times [82 (IQ 67–113) minutes; vs. 117 (93.5–139.5); vs. 102.5 (85.5–132.5), respectively (p < 0.0001)], a lower incidence of prolonged ventilator support [3.75% vs. 9.17 and 12.9%, respectively (p = 0.0034)], and required significantly shorter ICU and postoperative stays, resulting in an overall shorter hospitalization [6 (IQ 5–9) days; vs. 7 (5–14.5); vs 9 (6–15.5), respectively (p < 0.05)]. Incidence of other postoperative complications were lower in the mini-thoracotomy group compared to mini-sternotomy and conventional sternotomy, without significance. Minimally invasive techniques trended towards better survival [mini-thoracotomy 1.5%, mini-sternotomy 1.67%, and conventional sternotomy 5.17% (p = 0.13)].

Conclusions

Minimally invasive aortic valve replacement approaches are safe, effective alternatives to conventional sternotomy. The mini-thoracotomy approach showed decreased operative times, decreased lengths of stay, decreased incidence of prolonged ventilator time, and a trend towards lower mortality when compared to mini-sternotomy and conventional sternotomy.

The effect of minimally invasive surgical aortic valve replacement on postoperative pulmonary and skeletal muscle function

NEW FINDINGS

What is the central question of this study? How does surgical aortic valve replacement affect cardiopulmonary and muscle function during exercise? What is the main finding and its importance? Early after the surgical replacement of the aortic valve a significant decline in pulmonary function was observed, which was followed by a decline in skeletal muscle function in the subsequent weeks of recovery. These date reiterate, despite restoration of aortic valve function, the need for a tailored rehabilitation programme for the respiratory and peripheral muscular system.

ABSTRACT

Suboptimal post-operative improvements in functional capacity are often observed after minimally invasive aortic valve replacement (mini-AVR). It remains to be studied how AVR affects the cardiopulmonary and skeletal muscle function during exercise to explain these clinical observations and to provide a basis for improved/tailored post-operative rehabilitation. Twenty-two patients with severe aortic stenosis (AS) (aortic valve area (AVA) <1.0 cm²) were pre-operatively compared to 22 healthy controls during submaximal constant-workload endurance-type exercise for oxygen uptake ( V ̇ O 2 ), carbon dioxide output ( V ̇ C O 2 ), respiratory gas exchange ratio, expiratory volume ( V ̇ E ), ventilatory equivalents for O₂ ( V ̇ E / V ̇ O 2 ) and CO₂ ( V ̇ E / V ̇ C O 2 ), respiratory rate (RR), tidal volume (V_t ), heart rate (HR), oxygen pulse ( V ̇ O 2 /HR), blood lactate, Borg ratings of perceived exertion (RPE) and exercise-onset V ̇ O 2 kinetics. These exercise tests were repeated at 5 and 21 days after AVR surgery (n = 14), along with echocardiographic examinations. Respiratory exchange ratio and ventilatory equivalents ( V ̇ E / V ̇ O 2 and V ̇ E / V ̇ C O 2 ) were significantly elevated, V ̇ O 2 and V ̇ O 2 /HR were significantly lowered, and exercise-onset V ̇ O 2 kinetics were significantly slower in AS patients vs. healthy controls (P < 0.05). Although the AVA was restored by mini-AVR in AS patients, V ̇ E / V ̇ O 2 and V ̇ E / V ̇ C O 2 further worsened significantly within 5 days after surgery, accompanied by elevations in Borg RPE, V ̇ E and RR, and lowered V_t . At 21 days after mini-AVR, exercise-onset V ̇ O 2 kinetics further slowed significantly (P < 0.05). A decline in pulmonary function was observed early after mini-AVR surgery, which was followed by a decline in skeletal muscle function in the subsequent weeks of recovery. Therefore, a tailored rehabilitation programme should include training modalities for the respiratory and peripheral muscular system.

Minimally invasive surgery improves outcome of left ventricular assist device surgery in cardiogenic shock

Background

Left ventricular assist device (LVAD) (HVAD, Medtronic, Minneapolis, MN, USA) implantation is already a widely accepted treatment option for end-stage heart failure (HF) but also still considered as a rescue therapy for patients suffering from cardiogenic shock. Standard LVAD implantation techniques are often associated with high mortality rates and can result in severe complications, like bleeding or right heart failure (RHF). The aim of our study was to assess the outcome of Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) 1 patients (so called "crash and burn" patients) undergoing a LVAD implantation by standard or less invasive surgery.

Methods

We performed a retrospective evaluation of the 1-year outcome of 32 consecutive HF patients in cardiogenic shock, who underwent LVAD implantation in our institution. A total of 32 INTERMACS 1 patients were emergently operated. Fourteen patients (group A) were operated by using the "Hannover-VAD-technique", which is widely known to be less invasive (upper hemisternotomy and a left-sided anterolateral thoracotomy). In contrast, 18 patients (group B) were implanted with LVAD by using the standard technique (full sternotomy). The primary endpoint was survival after 1 year without device-related re-operations. Secondary endpoints included combined analyses of rates of RHF, respiratory failure and bleeding during the trial period.

Results

Baseline characteristics were similar in both groups. Survival after 1 year was higher in group A (69.7% vs. 50.0%). Technique-related adverse events (AEs) were also lower in the minimally invasive group, including a lower RHF (35.7% vs. 61.1%) and of further postoperative bleeding requiring surgery (14.3% vs. 33.3%).

Conclusions

LVAD surgery in INTERMACS 1 patients is associated with remarkably good outcome considering the already very high mortality of those patients, and compared to previously reported surgical outcomes. Our study indicates that minimally invasive LVAD implantation in cardiogenic shock decreases mortality and the incidence of postoperative AEs.

Reduction of driveline infections through doubled driveline tunneling of left ventricular assist devices-5-year follow-up

Background

Driveline infection (DLI) is one of the leading causes for unplanned re-admissions of patients undergoing therapy with left ventricular assist devices (LVAD). In previous studies our group was able to show that a double tunneling implantation technique could significantly reduce infection rates one year after implantation. We now report the results of the five-year-follow up of patients receiving the double tunneling technique.

Methods

We retrospectively analyzed patients receiving LVAD therapy with the HeartWare ventricular assist device (HVAD) (Medtronic, Minnesota, MN, USA) LVAD. For 36 patients (group 1) the driveline was tunneled via a conventional technique. In the remaining 33 patients (group 2) the drivelines were implanted by means of a double tunneling technique. The double tunnel driveline technique involved placement of the driveline in the sheath of the rectus muscle in the umbilical direction and then subcutaneously to the left (alternatively right) upper quadrant. We retrospectively compared both groups. Primary outcome parameters were infection rate and mortality.

Results

Five years after LVAD implantation the DLI rate of patients operated by a double tunneling technique was significantly lower than in the conventional technique group [61% (n=22) group 1 vs. 30% (n=10) group 2, P=0.004]. The 5-year mortality was lower in group 2 [42% (n=15) group 1 vs. 27% (n=9) group 2] but did not achieve statistical significance (P=0.10). The days of LVAD support between the two groups were comparable (1,275.56±885.89 group 1 vs. 1,321.94±711.37 group 2). The tunnel technique itself showed to be strongly associated with the occurrence of DLI. Other elevated variables are liver disease and dilated cardiomyopathy as primary disease.

Conclusions

Double tunneling technique for driveline implantation leads to significantly lowered infection rates after 5 years of LVAD therapy and it is associated with a lower mortality.

Clinical overview of the HVAD: a centrifugal continuous-flow ventricular assist device with magnetic and hydrodynamic bearings including lateral implantation strategies

Growing worldwide incidences of end-stage heart failure and declining rates of cardiac transplants have given rise to the need for alternative treatment options, based on mechanical circulatory support (MCS) devices such as left ventricular assist devices (LVADs). Technologically advanced LVADs such as the HVAD^® (HeartWare^®, Medtronic) facilitate safe and efficient treatment of heart failure patients with reduced post-operative complications, which is attributed to their considerably miniaturized size. This also facilitates the development and implementation of novel, minimally-invasive surgical techniques. The HVAD is a centrifugal pump, manufactured by HeartWare Inc., (Framingham, MA, USA) and subsequently by Medtronic Inc., (Minnesota, MN, USA), and has been approved for clinical application after receiving the CE Mark approval in 2008 and the FDA approval in 2012. Current research efforts are focused on further miniaturization alongside optimization of electronic and software controllers as well as implementation of the transcutaneous energy transfer (TET) technology. Salient features of the HVAD pump technology, clinical applications and future optimization strategies have been discussed in this article.

Right anterior mini-thoracotomy vs. conventional sternotomy for aortic valve replacement: a propensity-matched comparison

Background

Right anterior mini-thoracotomy (MIAVR) is a promising technique for aortic valve replacement. We aimed at comparing its outcomes with those obtained in a propensity-matched group of patients undergoing sternotomy at our two high-volume centers.

Methods

Main clinical and operative data of patients undergoing aortic valve replacement between January 2010 and May 2016 were retrospectively collected. A total of 678 patients were treated with a standard full sternotomy approach, while MIAVR was performed in 502. Propensity score matching identified 363 patients per each group.

Results

In-hospital mortality was not significantly different between the propensity-matched groups (1.7% in MIAVR patients vs. 2.2% in conventional sternotomy patients; P=0.79). No significant difference in the incidence of major post-operative complications was observed. Post-operative ventilation times (median 7, range 5-12 hours in MIAVR patients vs. median 7, range 5-12 in conventional sternotomy patients; P=0.72) were not significantly different between the two groups. Cardiopulmonary bypass time (61.0±21.0 vs. 65.9±24.7 min in conventional sternotomy group; P<0.01) and aortic cross-clamping time (48.3±16.7 vs. 53.2±19.6 min in full sternotomy group; P<0.01) were shorter in MIAVR group. EuroSCORE (OR 1.52, 95% CI, 1.12-2.06; P<0.01) was found to be the only independent predictor of intra-hospital mortality in the whole propensity-matched population.

Conclusions

Our experience shows that mini-access isolated aortic valve surgery is a reproducible, safe and effective procedure with similar outcomes and no longer operative times compared to conventional sternotomy.

Outcomes of Aortic Valve Replacement According to Surgical Approach in Intermediate and Low Risk Patients: A Propensity Score Analysis

BACKGROUND

Previous trials have shown that, among high-risk patients with aortic stenosis, survival rates are similar for transcatheter aortic-valve implantation (TAVI) and surgical aortic valve replacement. The study aimed to compare the outcomes of aortic valve replacement according to the adopted surgical approach in intermediate and low risk patients.

METHODS

This is a retrospective, observational, cohort study of prospectively collected data from 421 patients undergoing isolated aortic valve replacement between 2011 and 2015. A multinomial logit propensity score model based on preoperative risk factors was used to match patients 1:1:1 between conventional replacement (CAVR), minimally invasive (MIAVR) and TAVI groups, resulting in 50 matched three cohorts.

RESULTS

After multinomial logit propensity score, the three groups were comparable in terms of preoperative characteristics. Mean age and Logistic EuroSCORE I of CAVR, MIAVR and TAVI groups were (84.2±5.1 vs. 82.3±4.8 vs. 85.6±4.9 years; p=0.002) and (11.4±3.6% vs. 8.3±3.4% vs. 15.8±5.4%; p<0.001) respectively. Overall mortality rates were similar for the three patient cohorts at one year. There were no significant differences related to stroke to 30 days. In the TAVI cohort, pacemaker implantation for new-onset total atrioventricular block became necessary in 30% of patients (p<0.001) and 16% of patients had some degree of paravalvular aortic regurgitation, which was more than mild (p<0.001). Total length of stay was shorter in the TAVI group when compared with surgical groups (11.5±5.3 vs. 10.1±6.9 vs 8.5±3.7 days; p=0.023). After discharge, the survival rate follow-up (average follow up: 46.7 months) was 70%, 84% and 72% for three cohorts (log Rank x²=2.40, p=0.3).

CONCLUSIONS

In our experience, the three aortic valve replacement approaches offer very good results. Differences in the rate of complications were found between groups. Depending on patient's characteristics the Heart-Team group must offer the best surgical approach for each patient.

Left Ventricular Assist Device Therapy for Destination Therapy: Is Less Invasive Surgery a Safe Alternative?

INTRODUCTION AND OBJECTIVES

The number of older patients with congestive heart failure has dramatically increased. Because of stagnating cardiac transplantation, there is a need for an alternative therapy, which would solve the problem of insufficient donor organ supply. Left ventricular assist devices (LVADs) have recently become more commonly used as destination therapy (DT). Assuming that older patients show a higher risk-profile for LVAD surgery, it is expected that the increasing use of less invasive surgery (LIS) LVAD implantation will improve postoperative outcomes. Thus, this study aimed to assess the outcomes of LIS-LVAD implantation in DT patients.

METHODS

We performed a prospective analysis of 2-year outcomes in 46 consecutive end-stage heart failure patients older than 60 years, who underwent LVAD implantation (HVAD, HeartWare) for DT in our institution between 2011 and 2013. The patients were divided into 2 groups according to the surgical implantation technique: LIS (n = 20) vs conventional (n = 26).

RESULTS

There was no statistically significant difference in 2-year survival rates between the 2 groups, but the LIS group showed a tendency to improved patient outcome in 85.0% vs 69.2% (P = .302). Moreover, the incidence of postoperative bleeding was minor in LIS patients (0% in the LIS group vs 26.9% in the conventional surgery group, P < .05), who also showed lower rates of postoperative extended inotropic support (15.0% in the LIS group vs 46.2% in the conventional surgery group, P < .05).

CONCLUSIONS

Our data indicate that DT patients with LIS-LVAD implantation showed a lower incidence of postoperative bleeding, a reduced need for inotropic support, and a tendency to lower mortality compared with patients treated with the conventional surgical technique.

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.

Initial Experience with Aortic Valve Replacement via a Minimally Invasive Approach: A Comparison of Stented, Stentless and Sutureless Valves

Background

This study aimed to compare the short-term outcomes of MIS-AVR among 3 different types of biological heart valves.

Material/Methods

Complete data were obtained from 79 patients who underwent MIS-AVR between January 2010 and June 2015. Patients were divided into 3 groups: 27 patients (group A) received Medtronic 3f^® (Medtronic Inc., Fridley, MN, USA), 36 patients (group B) received DokimosPlus^® (LabCor Laboratórios Ltda., Belo Horizonte, Brazil) and 16 patients (group C) received Perceval^® (Sorin Biomedica Cardio S.r.l., Saluggia VC, Italy) valves.

Operative and postoperative parameters such as duration of operation, bypass time, duration of ventilation, morbidity, and mortality were statistically analyzed using the Kruskal-Wallis test. Hemodynamic assessment with transthoracic echocardiography was performed before discharge.

Results

The EuroSCORE II ranged between 0.67 and 6.94 with no significant difference between the groups. The median operative time was 166 min (range 90–230 min) in total, with significantly shorter times in group C (120 min [range 90–200]). The median total ventilation time was significantly lower in group C and significantly higher in group A. Hemodynamic evaluation demonstrated a mean maximal velocity (v_max) over the aortic valve of 2.3 m/s (range 0.9–4.3 m/s) with average mean and peak pressure gradient values of 10 mmHg (range 3–24 mmHg) and 20 mmHg (range 5–42 mmHg), respectively. Group A showed the highest values for v_max (H>5.99).

No significant difference was found regarding duration of hospitalization. Mortality was 3%.

Conclusions

In conclusion, all 3 valves showed good perioperative results, satisfying hemodynamic performance, and low complication rates.

Minimally Invasive Versus Conventional Aortic Valve Replacement: A Propensity-Matched Study From the UK National Data

Minimally invasive aortic valve replacement (MIAVR) has been demonstrated as a safe and effective option but remains underused. We aimed to evaluate outcomes of isolated MIAVR compared with conventional aortic valve replacement (CAVR).

Automated CTA based measurements for planning support of minimally invasive aortic valve replacement surgery

Minimally invasive aortic valve replacement (mini-AVR) procedures are a valuable alternative to conventional open heart surgery. Currently, planning of mini-AVR consists of selection of the intercostal space closest to the sinotubular junction on preoperative computer tomography images. We developed an automated algorithm detecting the sinotubular junction (STJ) and intercostal spaces for finding the optimal incision location. The accuracy of the STJ detection was assessed by comparison with manual delineation by measuring the Euclidean distance between the manually and automatically detected points. In all 20 patients, the intercostal spaces were accurately detected. The median distance between automated and manually detected STJ locations was 1.4 [IQR= 0.91-4.7] mm compared to the interobserver variation of 1.0 [IQR= 0.54-1.3] mm. For 60% of patients, the fourth intercostal space was the closest to the STJ. The proposed algorithm is the first automated approach for detecting optimal incision location and has the potential to be implemented in clinical practice for planning of various mini-AVR procedures.

Recent advances in aortic valve replacement for aortic stenosis

Aortic valve replacement is no longer an operation that is approached solely through a median sternotomy. Recent advances in the fields of transcatheter valves have expanded the proportion of patients eligible for intervention. Comparisons between transcatheter valves and conventional surgery have shown non-inferiority of transcatheter valve implants in patients with a high or intermediate pre-operative predictive risk. With advances in our understanding of sutureless valves and their applicability to minimally invasive surgery, the invasiveness and trauma of surgery can be reduced with potential improvements in outcome. The strategy of care has radically changed over the last decade.

Closed chest human aortic valve removal and replacement: Technical feasibility and one year follow-up

BACKGROUND

Minimally invasive aortic valve replacement has so far required a minithoracotomy or a ministernotomy. We present here the first series of totally endoscopic aortic valve replacement (TEAVR).

METHODS

Between June 2013 and April 2015, 14 consecutive patients (12 males, mean age=76 ± 5.4 years) with a mean EuroSCORE II of 2.72 ± 0.03% underwent TEAVR. A five trocar setting was used in all patients: after ablation of the native valve, a Nitinol stented sutureless 3f Enable Medtronic valve, compressed into the main working trocar, was introduced into the thorax and then expanded in the aortic root.

RESULTS

Among the 14 patients, a thoracoscopic approach was successful in 13 (92.8%) and conversion into an open surgery using the right anterior minithoracotomy was necessary to close the aortotomy in one case. Mean cross-clamping and cardiopulmonary (CPB) times were 112 ± 18 and 161 ± 31 min, respectively. All patients left the surgical unit within 8 days after the operation without any paravalvular leakage. There was no paravalvular regurgitation, conductive block or any major adverse event at a mean follow-up of 10 ± 4 months (range 2-16).

CONCLUSIONS

TEAVR is feasible and safe in a selected subset of patients. Closed chest surgery has the potential to become the future approach of the isolated aortic valve replacement in low risk patients but further technical refinement and larger studies are necessary to reduce operative durations and enhance reproducibility.

Influence of body mass index on outcomes after minimal-access aortic valve replacement through a J-shaped partial upper sternotomy

Background

Minimal-access aortic valve replacement (MAAVR) may reduce post-operative blood loss and transfusion requirements, decrease post-operative pain, shorten length stay and enhance cosmesis. This may be particularly advantageous in overweight/obese patients, who are at increased risk of post-operative complications. Obese patients are however often denied MAAVR due to the perceived technical procedural difficulty. This retrospective analysis sought to determine the effect of BMI on post-operative outcomes in patients undergoing MAAVR.

Methods

Ninety isolated elective MAAVR procedures performed between May 2006–October 2013 were included. Intra- and post-operative data were prospectively collected. Ordinary least squares univariate linear regression analysis was performed to determine the effect of BMI as a continuous variable on post-operative outcomes. One-way ANOVA and Chi-squared testing was used to assess differences in outcomes between patients with BMI <25 (n = 36) and BMI ≥25 (n = 54) as appropriate.

Results

There was no peri-operative mortality, myocardial infarction or stroke. Univariate regression demonstrated longer cross-clamp times (p = 0.0218) and a trend towards increased bypass times (p = 0.0615) in patients with higher BMI. BMI ≥25 was associated with an increased incidence of hospital-acquired pneumonia (p = 0.020) and new-onset atrial fibrillation (p = 0.036) compared to BMI <25. However, raised BMI did not extend ICU (p = 0.3310) or overall hospital stay (p = 0.2614). Similar rates of sternal wound complications, inotrope requirements and renal dysfunction were observed in both normal- and overweight/obese-BMI groups. Furthermore, increasing BMI correlated with reduced mechanical ventilation time (p = 0.039) and early post-operative blood loss (p = 0.004).

Conclusions

Our results demonstrate that within the range of this study, MAAVR is a safe, reproducible and effective procedure, affording equivalent clinical outcomes in both overweight/obese and normal-weight patients considered for an isolated first-time AVR, with low post-operative morbidity and mortality. MAAVR should therefore be considered as an alternative surgical strategy to reduce obesity-related complications in patients requiring aortic valve replacement.

HeartWare left ventricular assist device for the treatment of advanced heart failure

The importance of mechanical circulatory support in the therapy of advanced heart failure is steadily growing. The rapid developments in the field of mechanical support are characterized by continuous miniaturization and enhanced performance of the assist devices, providing increased pump durability and prolonged patient survival. The HeartWare left ventricular assist device system (HeartWare Inc., Framingham, MA, USA) is a mechanical ventricular assist device with over 8000 implantations worldwide. Compared with other available assist devices it is smaller in size and used in a broad range of patients. The possibility of minimally invasive procedures is one of the major benefits of the device – allowing implants and explants, as well as exchanges of the device with reduced surgical impact. We present here a review of the existing literature on the treatment of advanced heart failure using the HeartWare left ventricular assist device system.

Minimally-invasive LVAD Implantation: State of the Art

Nowadays, the worldwide number of left ventricular assist devices (LVADs) being implanted per year is higher than the number of cardiac transplantations. The rapid developments in the field of mechanical support are characterized by continuous miniaturization and enhanced performance of the pumps, providing increased device durability and a prolonged survival of the patients. The miniaturization process enabled minimally-invasive implantation methods, which are associated with generally benefitting the overall outcome of patients. Therefore, these new implantation strategies are considered the novel state of the art in LVAD surgery.

In this paper we provide a comprehensive review on the existing literature on minimally-invasive techniques with an emphasis on the different implantation approaches and their individual surgical challenges.

Minimally invasive ventricular assist device surgery

The use of mechanical circulatory support to treat patients with congestive heart failure has grown enormously, recently surpassing the number of annual heart transplants worldwide. The current generation of left ventricular assist devices (LVADs), as compared with older devices, is characterized by improved technologies and reduced size. The result is that minimally invasive surgery is now possible for the implantation, explantation, and exchange of LVADs. Minimally invasive procedures improve surgical outcome; for example, they lower the rates of operative complications (such as bleeding or wound infection). The miniaturization of LVADs will continue, so that minimally invasive techniques will be used for most implantations in the future. In this article, we summarize and describe minimally invasive state-of-the-art implantation techniques, with a focus on the most common LVAD systems in adults.

Current status of surgical treatment for aortic valve stenosis

In this review, we discuss the current surgical treatment for aortic valve stenosis. Surgical strategy for treatment of aortic valve stenosis is based on the risk profile of the patient. We reviewed the existing literature and present the current state of the art of these various approaches, taking into account clinical outcomes, quality of life, costs, and learning curve.

Perceval S sutureless aortic valve prosthesis implantation via a right anterior minithoracotomy

The rapid development and refinement of techniques over the past decade have led to the realization that a minimally invasive approach enables aortic valve surgery to be performed with results, at the very least, equivalent to those of traditional (open) valve surgery done in experienced centres. Minimally invasive aortic valve replacement (MIAVR) has now evolved into a safe, efficient treatment option providing greater patient satisfaction and fewer complications. For rapidly ageing population of industrialized countries, aortic valve replacement (AVR) has become the most frequent heart valve surgery. However, transcatheter aortic valve implantation techniques and sutureless aortic valve prostheses recently introduced into clinical practice are challenging now the results of MIAVR in certain high surgical risk patients. Right anterior minithoracotomy results in excellent exposure and a safe conduct of AVR. The minithoracotomy is performed via the second intercostal space with a 6-7&emsp14;cm long skin incision and no bone transection. After direct aortic and peripheral venous cannulation, aortic valve is exposed in a conventional manner, and further conduct of the intervention is not different from the sutureless AVR in median sternotomy. Herein, we discuss the indications, surgical technique and initial results of sutureless AVR through right anterior minithoracotomy.

Two axial-flow Synergy Micro-Pumps as a biventricular assist device in an ovine animal model

OBJECTIVE

This study investigated the use of 2 Synergy Micro-Pumps for full biventricular assist device (BiVAD) support. We examined right-sided and left-sided hemodynamic parameters over a range of right-sided and left-sided pump speeds in an acute, fibrillating, non-beating-heart model in sheep.

METHODS

Five juvenile sheep (43 ± 2 kg) were implanted with two Synergy Micro-Pumps (CircuLite Inc, Saddle Brook, NJ), 1 in the right (RV) and 1 in the left ventricle (LV), through a median sternotomy. The RVAD outflow graft was anastomosed end-to-side to the pulmonary artery and the LVAD outflow to the ascending aorta. After surgical implantation of both pumps, ventricular fibrillation was induced and hemodynamic parameters were measured at 9 different levels of RVAD pump speed (from 20,000 to 28,000 rpm at 1,000-rpm increments), while the speed of the LVAD was set constant at 24,000, then at 26,000, and finally, at 28,000 rpm.

RESULTS

At a fixed LVAD speed, RVAD and LVAD flow both increased identically as RVAD speed was increased. This was due to redistribution of blood volumes that resulted in resetting of pressure gradients across each pump and each vascular bed in a manner dictated by the pump pressure-flow characteristics. Results were similar with LVAD set at 24,000, 26,000, or 28,000 rpm. At the highest LVAD and RVAD speeds, flow averaged 3.1 ± 0.7 liters/min, and pressures in the right atrium, pulmonary artery, left atrium, and aorta averaged 2.2 ± 3.7, 24.4 ± 6.5, 22.4 ± 5.5, and 56.6 ± 8.5 mm Hg, respectively.

CONCLUSION

BiVAD support with the 2 Synergy Micro-Pumps is feasible and able to provide full hemodynamic support in sheep. This approach holds promise for providing biventricular partial support in humans and, in particular, for full support in small adults and children.

Influence of mild metabolic acidosis on cardiac contractility and isoprenaline response in isolated ovine myocardium

The postoperative course after major surgical procedures such as cardiothoracic operations is often accompanied by acute metabolic abnormalities due to large volume and temperature shifts. In general, those intervention-induced trauma might cause the use of catecholamines to stabilize hemodynamics. Within the cardiac community, there are still controversial discussions about standardized medical therapy to treat postoperative acidosis, for example, buffering versus nonbuffering for improving catecholaminergic response of myocardial contractility. The aim of this study was to investigate the influence of mild (and thus clinically relevant) acidosis on myocardial contractility and catecholamine response in explanted trabeculae of ovine hearts. Intact trabeculae (n = 24) were isolated from the right ventricle of healthy sheep hearts. Two different groups (group 1: pH = 7.40, n = 9 and group 2: pH = 7.20, n = 13) were investigated, and force amplitudes were measured at frequencies between 30 and 180 beats per minute and increasing catecholamine concentrations (isoprenaline 0-3 × 10(-6) mM). Force-frequency relation experiments in the presence of a physiological and/or mild acidotic pH solution showed no significant differences. Mean force amplitudes normalized to the lowest frequency showing no significant differences in force development between 0.5 and 3 Hz (n = 9 vs. 13, P = n.s.) (0.5 Hz absolute values 3.1 ± 2.6 for pH = 7.40 vs. 3.8 ± 2.6 mN/mm(2) for pH = 7.20, P = n.s.). Moreover, there was no significant difference in relaxation kinetics between the two groups. Furthermore, the experiments showed similar catecholamine responses in both groups. Force amplitudes normalized to baseline and maximum force showed no significant differences in force development between baseline and maximum isoprenaline concentrations (n = 6 vs. 9, P = n.s.) (baseline absolute values 4.3 ± 4.0 for pH = 7.40 vs. 3.9 ± 1.2 mN/mm(2) for pH = 7.20, P = n.s.). Additionally, relaxation kinetics did not show differences after catecholamine stimulation. The presented experiments revealed no significant negative inotropic effects on isometrically contracting ovine trabeculae with mild metabolic acidosis (pH = 7.2) compared with physiological pH (7.4). Additionally, similar catecholamine responses were seen in both groups. Further investigations (e.g., in vivo and/or in failing hearts with reduced compensatory reserves) will be necessary to examine optimal medical treatment for metabolic abnormalities after cardiac surgery.

Technique for chest compressions in adult CPR

Chest compressions have saved the lives of countless patients in cardiac arrest as they generate a small but critical amount of blood flow to the heart and brain. This is achieved by direct cardiac massage as well as a thoracic pump mechanism. In order to optimize blood flow excellent chest compression technique is critical. Thus, the quality of the delivered chest compressions is a pivotal determinant of successful resuscitation. If a patient is found unresponsive without a definite pulse or normal breathing then the responder should assume that this patient is in cardiac arrest, activate the emergency response system and immediately start chest compressions. Contra-indications to starting chest compressions include a valid Do Not Attempt Resuscitation Order. Optimal technique for adult chest compressions includes positioning the patient supine, and pushing hard and fast over the center of the chest with the outstretched arms perpendicular to the patient's chest. The rate should be at least 100 compressions per minute and any interruptions should be minimized to achieve a minimum of 60 actually delivered compressions per minute. Aggressive rotation of compressors prevents decline of chest compression quality due to fatigue. Chest compressions are terminated following return of spontaneous circulation. Unconscious patients with normal breathing are placed in the recovery position. If there is no return of spontaneous circulation, then the decision to terminate chest compressions is based on the clinical judgment that the patient's cardiac arrest is unresponsive to treatment. Finally, it is important that family and patients' loved ones who witness chest compressions be treated with consideration and sensitivity.

Surgical Approaches to Aortic Valve Replacement and Repair-Insights and Challenges

Since 1960, surgical aortic valve replacement (sAVR) had been the only effective treatment for symptomatic severe aortic stenosis until the recent development of transcatheter aortic valve replacement (TAVR). TAVR has offered an alternative, minimally invasive treatment approach particularly for patients whose age or co-morbidities make them unsuitable for sAVR. The rapid and enthusiastic utilization of this new technique has triggered some speculation about the imminent demise of sAVR. We believe that despite the recent advances in TAVR, surgical approach to aortic valve replacement has continued to develop and will continue to be highly relevant in the future. This article will discuss the recent developments and current approaches for sAVR, and how these approaches will keep pace with catheter-based technologies.