Expanding the Minimally Invasive Approach towards the Ascending Aorta-A Practical Overview of the Currently Available Techniques

Minimally invasive techniques have gained immense importance in cardiovascular surgery. While minimal access strategies for coronary and mitral valve surgery are already widely accepted and often used as standard approaches, the application of minimally invasive techniques is currently expanded towards more complex operations of the ascending aorta as well. In this new and developing field, various techniques have been established and reported ranging from upper hemisternotomy approaches, which allow even extensive operations of the ascending aorta to be performed through a minimally invasive access to sternal sparing thoracotomy strategies, which completely avoid sternal trauma during ascending aorta replacements. All of these techniques place high demands on patient selection, preoperative planning, and practical surgical implementation. Application of these strategies is currently limited to high-volume centers and highly experienced surgeons. This narrative review gives an overview of the currently available techniques with a special focus on the practical execution as well as the advantages and disadvantages of the currently available techniques. The first results demonstrate the practicability and safety of minimally invasive techniques for replacement of the ascending aorta in a well-selected patient population. With success and complication rates comparable to classic full sternotomy, the proof of concept for minimally invasive replacement of the ascending aorta is now achieved.

Microembolic signal monitoring in patients with HeartMate 3 and HeartWare left ventricular assist devices: Association with antithrombotic treatment and cerebrovascular events

BACKGROUND

In patients with left ventricular assist devices (LVADs), ischemic and hemorrhagic stroke are dreaded complications. Predictive markers for these events are lacking. This study aimed to investigate the prevalence and predictive value of microembolic signals (MES) for stroke, detected by Transcranial Doppler sonography (TCD) in patients with HeartMate 3 (HM 3) or HeartWare (HW).

METHODS

A thirty-minute bilateral TCD monitoring of the middle cerebral artery (MCA) was performed in 62 outpatients with LVAD (HM 3 N = 31, HW N = 31) and 31 healthy controls. Prevalence and quantity of MES were investigated regarding clinical and laboratory parameters. Cerebrovascular events (CVE) were recorded on follow-up at 90 and 180 days.

RESULTS

MES were detected in six patients with HM 3, three patients with HW, and three controls. Within the LVAD groups, patients on monotherapy with vitamin-K-antagonist (VKA) without antiplatelet therapy were at risk for a higher count of MES (negative binomial regression: VKA: 1; VKA + ASA: Exp(B) = 0.005, 95%CI 0.001-0.044; VKA + clopidogrel: Exp(B) = 0.012, 95%CI 0.002-0.056). There was no association between the presence of MES and CVE or death on follow-up (p > 0.05).

CONCLUSION

For the first time, the prevalence of MES was prospectively investigated in a notable outpatient cohort of patients with HM 3 and HW. Despite optimized properties of the latest LVAD, MES remain detectable depending on antithrombotic therapy. No association between MES and CVE could be detected.

Vascular procedures in patients with left ventricular assist devices: single-center experience

Objective

A growing number of patients suffering from heart failure is living with a left ventricular assist device (LVAD) and is in the need for non-cardiac surgery. Vascular procedures due to ischemia, bleeding, or other device-related complications may be required and pose a challenge to the caregivers in terms of monitoring and management of these patients. Therefore, we reviewed our experience with LVAD patients undergoing vascular surgery.

Methods

From January 2010 until March 2017, a total of 54 vascular procedures were performed on 41 LVAD patients at our institution. Patient records were reviewed retrospectively in terms of incidence of LVAD-related complications, including thrombosis, stroke, bleeding, wound healing, and survival associated with vascular surgery. The type of surgery was recorded, as well as various clinical demographic variables.

Results

Vascular procedures were performed in 35 men (85.4%) and 6 women (14.6%) with LVADs. There were no perioperative strokes, device thromboses, or device malfunctions. Thirty-day mortality overall was 26.8% (eleven patients), with most patients dying within 30 days after LVAD implantation due to multi-organ failure. In 25 procedures (46.3%), a blood transfusion was necessary.

Conclusion

Patients on LVAD support are a complex cohort with a high risk for perioperative complications. In a setting where device function and anticoagulation are monitored closely, vascular surgery in these patients is feasible with an acceptable perioperative risk.

Mid-term Outcome of the Edge-To-Edge Mitral Valve Repair Via Aortic Outflow Tract in High-Risk Patients

The edge-to-edge mitral valve repair technique, invented by Alfieri and colleagues, introduced valve repair as a treatment option for patients with complex diseases where standard annuloplasty and related repair techniques are insufficient, due to annular calcification and patient frailty. We retrospectively evaluated the results of a transaortic edge-to-edge mitral valve repair (Alfieri stitch) in high-risk patients who were undergoing aortic valve replacement. From February, 2012 to December, 2017, 43 patients underwent transaortic edge-to-edge mitral valve repair with concomitant aortic valve replacement at a single institution. Preoperative and postoperative echocardiograms were compared. Home telephone follow up was conducted and postoperative morbidity was examined, including the need for reoperation, stroke and cardiac arrhythmia. 30-day and long-term survival rates were also determined. Mitral regurgitation (MR) was graded semi-quantitatively as 0 (trace and/or none), mild (1), moderate (2) or moderate to severe (3-4). The patients were 74 ± 7.8 years old. 65% of the patients were male. Mean cardiopulmonary bypass time was 115 ± 37 minutes and mean cross-clamp time was 71 ± 23 minutes. There was a significant improvement in preoperative vs postoperative median MR grade (2 (IQR 2-3) vs 0 (IQR 0-1); P = 0.05). Follow-up transthoracic echocardiograms in 29 patients obtained at a median of 9 months' (range 3 - 19 months') and in 16 patients at a median of 34 months' postoperatively (range 21 - 53 months') showed mild (1 (IQR 1-2)) grade of mitral regurgitation. 30-day survival was 98%. Long term survival at 12 and 24 months' were 88% and 81% respectively. Mitral valve reoperation was conducted in 1 patient (2%), who was suffering of endocarditis. Stroke occurred in 2 patients (7%). Cardiac arrhythmia was observed in 15 patients (35%). 8 patients (19%) suffered from atrial fibrillation and 7 patients (16%) displayed atrioventricular blockage. 10 patients (23%) could be treated conservatively and 5 patients (12%) needed implantation of a pacemaker. Transaortic edge-to-edge mitral valve repair can be safely performed during aortic valve replacement in high-risk patients and improves even long-term MR grade. Postoperative cardiac arrhythmia occurs frequently. 66% of them could be treated successfully by conservative procedures.

A new era of ventricular assist device surgery: less invasive procedures

As the number of patients suffering of congestive heart failure is rising worldwide, the use of mechanical circulatory support to treat these patients has also grown enormously, surpassing the number of annual heart transplants. Moreover latest generation of left ventricular assist devices (LVADs) is characterized by improved technologies. Moreover the size of new LVAD systems is considerably reduced when compared to older generation devices. Therefore, less invasive surgery is now possible for the implantation, explantation, and exchange of LVADs. Although experience with these new techniques is still limited, minimally invasive procedures are thought to improve surgical outcomes by declining 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 LVAD-related procedures in the future. In this article, we summarize and describe minimally invasive surgical techniques, with a focus on the most common LVAD systems in adults.