Conduction Disorders after Surgical Aortic Valve Replacement Using a Rapid Deployment Aortic Valve Prosthesis: Medium-Term Follow-Up

BACKGROUND

We have previously reported that the incidence of postoperative conduction disorders, especially left bundle branch block (LBBB), after implantation of a rapid deployment Intuity™ Elite aortic valve prosthesis (Edwards Lifesciences, Irvine, CA, USA), was significantly increased compared with conventional aortic valve replacement. We were now interested in how these disorders behaved at intermediate follow-up.

METHODS

All 87 patients who had undergone surgical aortic valve replacement (SAVR) using the rapid deployment Intuity™ Elite prosthesis and were shown to have conduction disorders at the time of hospital discharge were followed up after surgery. These patients' ECGs were recorded at least 1 year after surgery, and the persistence of the new postoperative conduction disorders was assessed.

RESULTS

At hospital discharge, 48.1% of the patients had developed new postoperative conduction disorders, with LBBB being the predominant conduction disturbance (36.5%). At medium-term follow-up (526 days, standard deviation (SD) = 169.6, standard error (SE) = 19.3 days, respectively), 44% of the new LBBB and 50% of the new right bundle branch block (RBBB) had disappeared. There was no new atrio-ventricular block III (AVB III) that occurred. One new pacemaker (PM) was implanted during follow-up because of AVB II Mobitz type II.

CONCLUSIONS

At medium-term follow-up after the implantation of a rapid deployment Intuity™ Elite aortic valve prosthesis, the number of new postoperative conduction disorders, especially LBBB, has considerably decreased but remains high. The incidence of postoperative AV block III remained stable.

Coronary Anastomosis In Stent-Useful to Do When No Other Alternative Is Given?

Background  Many patients being referred for coronary artery bypass grafting have a history of percutaneous coronary intervention (PCI). Case Description  In a patient after multiple PCI of the left anterior descending artery (LAD), repeated in-stent stenosis was diagnosed. The LAD being covered with stents to the periphery, no meaningful anastomosis with stent-free vessel was possible. After thorough discussion with the patient, the referring cardiologist, and our local heart team, an in-stent anastomosis was planned and created, that was found to be angiographically patent 21 months after surgery with the patient free from angina. Conclusion  Without any alternative treatment method given, our approach of in-stent anastomosis confers a good mid-term angiographic result.

Pass On What You Have Learned: A Structured Mentor-Mentee Concept for the Implementation of a Minimally Invasive Mitral Valve Surgery Program

INTRODUCTION

Starting a minimally invasive cardiac surgery (MICS) for mitral valve repair (MVR) program is challenging as it requires a new learning curve, but compromising surgical results at the same time is not acceptable. Here, we describe our surgical educational experience of starting a new MICS program at a university heart center in Germany.

METHODS

A dedicated team for the new MICS program including 2 cardiac surgeons, 1 cardiac anesthetist, 1 perfusionist, and 1 scrub nurse was chosen. The use of long shafted instruments was trained in a low-cost self-assembled MICS simulator, and the EACTS endoscopic dry lab course was visited. Thereafter, 1 MICS center was visited for direct observation and peer-to-peer education for 6 weeks. The mentor observed the first 10 cases performed by the mentee. The surgical mitral valve expertise of 1 single cardiac surgeon was retrospectively analyzed between April 2016 and April 2021.

RESULTS

Before the implementation of the MICS-MVR program, 18 mitral valve operations have been performed through sternotomy between April 2016 and October 2018 including 12 replacements and 6 ring annuloplasties. After starting the MICS-MVR program, 73 mitral operations have been performed by the same surgeon of which 53 video-assisted through minithoracotomy (72.6%). 83.1% of the MICS procedures included complex repair (n = 38) and ring annuloplasty (n = 6). Open heart MV surgery was necessary in 20 patients due to concomitant procedures (n = 8), redo procedures (n = 2), severe endocarditis (n = 4), or contraindication for MICS such as PAD (n = 6). There have been no deaths, 1 stroke, and 1 cardiac vascular (RCX) complication. Two patients required conversion to sternotomy and one pericardiocentesis in the long term.

CONCLUSION

Typically, excellent exposure and high repair rates of the MV has led us offer MICS approach to a majority of patients with isolated MV disease. Careful planning and a strict mentor-mentee concept facilitated a safe startup of an MICS program in a busy university heart center.

Concomitant tumourous lesions in the left atrium and aortic valve suspected to be myxoma

The occurrence of multiple primary cardiac tumours in a single patient is extremely rare. Despite growing expertise in non-invasive diagnostic modalities, especially in transoesophageal echocardiography, only a few cases report the coincidence of papillary fibroelastoma of the aortic valve and myxoma of the left atrium. Moreover, echocardiographic as well as a macroscopic distinction between cardiac myxoma and cardiac fibroelastoma may be difficult. Only post-excisional histopathology provides diagnostic safety. Cryoablation of the remnant tissue prevents recurrence in both the aortic valve and the left atrium.

Impact of pre-existing comorbidities on outcomes of patients undergoing surgical aortic valve replacement - rationale and design of the international IMPACT registry

Background

Degenerative aortic valve disease accounts for 10–20% of all cardiac surgical procedures. The impact of pre-existing comorbidities on the outcome of patients undergoing surgical aortic valve replacement (SAVR) needs further research.

Methods

The IMPACT registry is a non-interventional, prospective, open-label, multicenter, international registry with a follow-up of 5 years to assess the impact of pre-existing comorbidities of patients undergoing SAVR with the INSPIRIS RESILIA aortic valve on outcomes. IMPACT will be conducted across 25 sites in Austria, Germany, The Netherlands and Switzerland and intends to enroll approximately 500 patients. Patients will be included if they are at least 18 years of age and are scheduled to undergo SAVR with the INSPIRIS RESILIA Aortic Valve with or without concomitant ascending aortic root replacement and/or coronary bypass surgery. The primary objective is to determine all-cause mortality at 1, 3, and 5 years post SAVR. Secondary objectives include cardiac-related and valve-related mortality and structural valve deterioration including hemodynamics and durability, valve performance and further clinical outcomes in the overall study population and in specific patient subgroups characterized by the presence of chronic kidney disease, hypertension, metabolic syndrome and/or chronic inflammation.

Discussion

IMPACT is a prospective, multicenter European registry, which will provide much-needed data on the impact of pre-existing comorbidities on patient outcomes and prosthetic valve performance, and in particular the performance of the INSPIRIS RESILIA, in a real-world setting. The findings of this study may help to support and expand appropriate patient selection for treatment with bioprostheses.

Trial registration

ClinicalTrials.gov identifier: NCT04053088.

Tricuspid valve repair in acute endocarditis in a young patient with active IV drug abuse

Right-sided infective endocarditis is common in patients who use intravenous drugs. However, even when leaflets are heavily damaged as a result of the endocarditis, an attempt of valve repair is worth a try. Tricuspid valve repair is superior to valve replacement because it is associated with  a lower rate of recurrence and reoperation.

Massive Left Atrial Thrombus in Two Patients with Heparin-Induced Thrombocytopenia Type II after Cardiac Surgery

Heparin-induced thrombocytopenia type II (HIT type II) can have devastating consequences in cardiac surgical patients. We report two cases of massive left atrial thrombus after mitral valve replacement and endocardial cryoablation in patients with HIT type II.

Evolution of a minimally invasive mitral valve program

Minimally invasive valve surgery is evolving into a procedure of choice in the treatment of mitral regurgitation (MR). Visualization techniques have improved vastly over the past decades. With the use of 3D technology rib retractors can be avoided, incision size has come down to a minimum without reducing and even improving the surgeons view.

Freezing Equals Freezing? Performance of Two Cryoablation Devices in Concomitant Mitral Valve Repair

Background Recent guidelines have recommended the addition of ablation in cardiac surgery for patients presenting with atrial fibrillation (AF). Currently available cryoablation devices use either nitrous oxide or argon gas as cooling agent. Our study aimed to compare success rates of two different devices currently available on the market and applied during concomitant cardiac surgery. Methods Between 2009 and 2012, data were collected from 120 consecutive patients in whom either the aluminum cryoICE ablation probe (AtriCure, Inc., Cincinnati, Ohio, United States) using nitrous oxide or the stainless steel Cardioblate CryoFlexTM 10-S probe (Medtronic, Inc., Minneapolis, Minnesota, United States) using argon gas was applied for concomitant ablation procedures in minimally invasive mitral valve cases. Perioperative variables, myocardial injury biomarkers (MIBs) and Holter monitoring results were compared. Results Perioperative variables such as sex, age, type, and duration of AF, procedure and cross-clamp times, and 30-day mortality did not significantly differ between the groups. Postoperative peak creatinine kinase MB (CK-MB) levels were significantly higher in the nitrous oxide group (p = 0.047). At a mean follow-up of 20 ± 13 months, freedom from AF was significantly higher in the nitrous oxide group (87%) compared with the argon group (71%, p = 0.044). Left atrial (LA) diameter and device used were the only predictors of failure of ablation (p = 0.029 and p = 0.018, respectively). Conclusion The nitrous oxide-based aluminum probe revealed a better outcome than the argon-based stainless steel probe. Besides the cooling agent, probe material and probe-tissue interface might have contributed to the better performance of the cryoICE probe.

Safety and feasibility of a novel adjustable mitral annuloplasty ring: a multicentre European experience

OBJECTIVES

Recurrent mitral regurgitation is a significant problem after mitral valve repair in patients with functional valve disease. We report the safety and feasibility of a novel adjustable mitral annuloplasty device that permits downsizing of the anterior–posterior diameter late after initial surgery.

METHODS

In this multicentre, non-randomized, observational register, patients with moderate or severe mitral regurgitation undergoing surgical mitral valve repair with the MiCardia EnCor_SQ™ Mitral Valve Repair system were evaluated. Patient characteristics, operative specifications and results as well as postoperative follow-up were collected for all five centres.

RESULTS

Ninety-four patients with a median age of 71 (64–75) years (EuroSCORE II 6.7 ± 6.3; 66% male, 48% ischaemic MR, 37% dilated cardiomyopathy and 15% degenerative disease) were included. Operative mortality was 1% and the 1-year survival was 93%. Ring adjustment was attempted in 12 patients at a mean interval of 9 ± 6 months after surgery. In three of these attempts, a technical failure occurred. In 1 patient, mitral regurgitation was reduced two grades, in 2 patients mitral regurgitation was reduced one grade and in 6 patients, mitral regurgitation did not change significantly. The mean grade of mitral regurgitation changed from 2.9 ± 0.9 to 2.1 ± 0.7 (P = 0.02). Five patients were reoperated after 11 ± 9 months (Ring dehiscence: 2; failed adjustment: 3).

CONCLUSION

We conclude that this device may provide an additional treatment option in patients with functional mitral regurgitation, who are at risk for reoperation due to recurrent mitral regurgitation. Clinical results in this complex disease were ambiguous and patient selection seems to be a crucial step for this device. Further trials are required to estimate the clinical value of this therapeutic concept.

Experimental transapical endoscopic ventricular visualization and mitral repair

BACKGROUND

An increasing number of experimental beating heart animal studies describe simple transapical mitral valve repairs based on the direct endoscopic visualization of the left ventricle. The aim of our human cadaveric study was to develop a method for more complex transapical endoscopic procedures by on-pump heart operations.

MATERIALS AND METHODS

After preparation of 20 human fresh cadavers, a standard left anterolateral minithoracotomy was performed in the fifth intercostal space and the pericardium was entered. A rigid 0 degree endoscope and the instruments were introduced through a silicon apical port. To restore the natural form of the left heart, CO2 was insufflated. To test the mitral valve competence, the left ventricle was pressure-injected with saline after each step. After transecting the chords of the A2 segment of the anterior mitral leaflet before the experimental mitral valve repair, the tendinous chord was replaced using an especially designed clip chord. The second part of the experiment consisted of a segmental excision of the P2 segment of the posterior mitral leaflet followed by a standard valvuloplasty and suture annuloplasty.

RESULTS

With the help of the described transapical endoscopic mitral valve repair technique, we gained direct visual information of the coaptation line of the mitral leaflets as well as the anatomy and function of the subvalvular apparatus. Using intracardiac imaging, we could perform successful transapical complex mitral repair in each case.

CONCLUSION

The minimally invasive transapical endoscopic method has the potential to offer advantages for on-pump mitral valve repair procedures even in complex mitral valve repair cases.

Adjustable mitral annuloplasty for the surgical treatment of ischaemic mitral insufficiency

Presentation of the MiCardia enCorSQ annuloplasty device implantation technique for ischaemic mitral regurgitation including late-stage activation: exposure of mitral valve using video-assisted right lateral mini-thoracotomy, annuloplasty, tunnelling of permanently attached lead through the left atrial wall and subcutaneous implantation; and late activation: minor cut-down procedure for lead exposure, connection to proprietary energy source (MC-100 RF generator), echocardiography and fluoroscopy guidance, anterior-posterior diameter reduction of memory-shape alloy core annuloplasty device by raising the temperature a few degrees above body temperature.

Comparative endoscopic anatomic description of the mitral valvular complex: a cadaveric study

BACKGROUND

We compared the aortic, left atrial, and apical approaches to visualize the mitral valve with the goal to investigate the endoscopic anatomy and give exact step-by-step descriptions of these views.

MATERIALS AND METHODS

The mitral valvular complex of human cadaveric fresh hearts was investigated from three approaches using 0, 30, and 70 degrees rigid endoscopic optics. In 30 cases after the removal of the hearts, the endoscopes were introduced directly into the aortic root through an aortotomy, left atrium through a standard atriotomy, and apex of the heart through a transmural incision. In 10 cases, the in situ visualization was performed using standard surgical approaches, such as partial upper ministernotomy, right and left minithoracotomy. The investigation was performed first with the mitral valve open, then the left ventricle was filled with saline, and the valve was closed by clamping the aorta.

RESULTS

For the visualization of ventricular surfaces of the mitral leaflets and the subvalvular apparatus, the apical approach was most optimal. The aortic approach had limitations at the posterior leaflet. Using the atrial approach, we did not obtain any direct visual information about the subvalvular apparatus with the valve closed. The atrial surfaces of the leaflets were best visible using both the atrial and apical approaches with the mitral valve open. In the case of a closed valve, the apical approach did not allow for an investigation of the atrial surfaces. The aortic approach was useful to visualize the atrial surface of the posterior leaflet with an opened valve.

CONCLUSION

In mitral valve repairs through the left atrium, an additional aortic or apical view could be useful to obtain functional information about the subvalvular apparatus by the sealing probe.

Safeguards and pitfalls in minimally invasive mitral valve surgery

Minimally invasive mitral valve surgery has been established in many institutions worldwide. Appropriate indications and patient selection for this procedure must be based on a thorough understanding of its limitations and specific pitfalls. Particular risks can be minimized with careful attention to detail when planning and performing the surgery. The following chapter offers a stepwise description of the procedure; we point out particular advantages, discuss our rationale for certain steps, as well as focus on potential dangers of minimally invasive mitral valve surgery. Several graphics have also been provided to illustrate our approach and demonstrate important structural and anatomical concepts of the mitral valve apparatus.

Successful postoperative activation of an adjustable annuloplasty ring (MiCardia) in recurrent ischemic mitral valve regurgitation

We report the case of a 73-year-old patient with severe ischemic mitral regurgitation (MR). She subsequently underwent combined coronary artery revascularization and mitral valve annuloplasty using the adjustable enCorSQ device (MiCardia Corporation, Irvine, CA). Three months later she experienced recurrent symptomatic severe MR. Accessing the subcutaneous lead, activation and downsizing of the device within 45 seconds resulted in trace MR. The result was unchanged 1 month later.

Unusual cause of acute back pain mimicking aortic dissection: a case report

We report the case of a 62-year-old woman who initially presented with symptoms suggesting acute type A aortic dissection. Imaging studies revealed hemorrhagic pericardial fluid without the evidence of dissection. Foreign body material was noted floating in the inferior vena cava (IVC) and also piercing the right ventricular wall. Upon surgical exploration, the extracted material could be identified to be acrylic bone cement (palacos). The patient had reported a history of kyphoplasty in 2008.

[Efficacy and safety of various energy sources and application techniques for the surgical treatment of atrial fibrillation]

We investigated efficacy and safety of different energy sources and application techniques for the treatment of atrial fibrillation in an experimental acute sheep model. In particular, we focused on thermal damage to the adjacent structures and tissues. We also attempted to evaluate the efficacy of different application techniques such as endocardial or epicardial approaches. Overall 64 young Merino sheep were examined. It could be shown that endocardial ablation with different energy sources on cardiopulmonary bypass consistently caused histomorphologically and electrophysiologically transmural lesions. Depending on the energy source, different amounts of endocardial damage were induced. Cryoapplication produces the smallest endocardial laceration without thrombus formation. Dry radiofrequency energy and microwave produced very wide and diffuse endocardial damage with carbonisation and disruption of the endothelium. Epicardial ablation on a beating heart (off-pump) with bipolar radiofrequency was consistently effective. Due to the energy flow between the two jaws of the bipolar clamp, no collateral damage was observed. All other energy sources were unable to produce transmural lesions epicardially (off-pump) because the nearby blood flow rewarmed or recooled the myocardium and caused the so called "heat sink phenomenon". Depending on the energy source, different histomorphological changes in the esophagus could be observed. Changes in intraluminal-measured esophageal temperatures were not observed during ablation.

Cardiomyoplasty - improvement of muscle fibre type transformation by an anabolic steroid (metenolone)

Dynamic cardiomyoplasty, a method to support ventricular function by the chronically stimulated latissimus dorsi muscle wrapped around the heart is accompanied by a loss of mass and force of the transplanted muscle. These effects and the fast-to-slow transformation of the muscle could be possibly influenced by the additional administration of anabolic steroids. In this study, the left latissimus dorsi muscles of 12 sheep were electrically conditioned (group A). In 12 other animals (group B), stimulation was combined with the administration of metenolone (100 mg/week). Biopsies were taken from the right and left muscles at the beginning and after 6 and 12 weeks of treatment, frozen and cross-sectioned. The muscle fibre type composition was studied enzymhistochemically (SDH-staining and Myosin-ATPase-reaction) and immunocytochemically (using antibodies against different myosin heavy chains, MHC). Furthermore, the expression of different MHC isoforms was investigated electrophoretically. The untreated latissimus dorsi muscle contains 20% type I fibres expressing slow MHC and 80% type II fibres expressing fast MHC. After 6 weeks, the respective fibre type composition was 42 and 58% (group A) and 80 and 20% (group B). After 12 weeks, the percentage of the type I fibres rose in group A to 59% and in group B to 98%. In accordance with these morphological results, the MHC pattern determined electrophoretically showed a corresponding shift from the fast to the slow isoform. Therefore, the administration of metenolone avoids severe muscle atrophy, and improves and accelerates fast to slow fibre type conversion necessary for successful cardiomyoplasty.