Ralf Krakor

The evolution of minimally invasive mitral valve surgery – 2 year experience

Objectives: The aim of the study was to evaluate the evolution of Port-Access minimally invasive mitral valve surgery to a robot assisted video assisted solo surgery approach. Methods: One hundred and twenty-nine patients with non-ischemic mitral valve disease underwent 3D-video assisted mitral valve surgery via a 4 cm right lateral minithoracotomy using femoro-femoral bypass and endoaortic clamping. Transcranial Doppler and continuous transesophageal echocardiography were used to monitor placement and positional stability of the endoclamp. After the initial series (group I, n = 62), a simplified solo surgical technique using voice controlled robotic assistance for videoscope guidance was used in the last 67 patients (group II). Results: After an initial learning curve and modifications of catheter design, the procedure could be steadily redefined and simplified. In the last 67 patients, the procedure was completed without the need for an additional assistant as ‘solo surgery’. The mitral valve was repaired in 72 and replaced in all other patients. Duration of bypass and clamp time steadily improved during our study and in the most recent 67 patients average 107 ∠ 34 and 48 ∠ 16 min, respectively. The voice controlled robotic arm (AESOP 3000, Automated Endoscope System for Optimal Positioning) provided a stable and precise video image with excellent exposure of all valvular and subvalvular structures. Hospital mortality was high in the early series (mean survival 88.7% at 804 ∠ 35 days; 95% CI: 735‐873) and partially procedure related (aortic dissection in two patients). In group II, hospital mortality has declined to 3.0% (mean survival 97.0% at 568 ∠ 12 days; 95% CI: 553‐600). Conclusion: Port-Access minimally invasive mitral valve surgery has evolved to be a reliable video assisted technique with reproducible results. Surgery can now be performed almost in the same time as with conventional techniques. Robotic assistance has enabled a solo surgery approach.

Intraoperative left atrial ablation (for atrial fibrillation) using a new argon cryocatheter: early clinical experience

PURPOSE Recently surgical treatment of atrial fibrillation has gained more popularity and presently is being performed in large numbers of patients. This report describes our early experience in treatment of patients with chronic or paroxysmal atrial fibrillation with a new tool for left atrial cryoablation. DESCRIPTION From July 2002 through January 2003, 28 patients underwent left atrial cryoablation with the Surgifrost CryoCath. Patients underwent cryotherapy as an isolated procedure (n = 1), in combination with mitral valve surgery (n = 13), or with other surgical procedures (n = 14). In all patients contiguous lesion lines to the orifices of the pulmonary veins connected to the mitral annulus and the atriotomy were created. Surgery was performed through a conventional sternotomy in 8 patients (29%) and a right lateral minithoracotomy using video-assistance in 20 patients (71%). EVALUATION Postoperatively sinus rhythm was restored in 27 patients (96%). At discharge 82% (23/28) of patients were in sinus rhythm and 18% (5/28) were in atrial fibrillation. Four patients (14%) required pacemaker implantation. There was no in-hospital mortality. At 6-months follow-up (19/28 patients) all were alive and 74% were in stable sinus rhythm, New York Heart Association functional class was 1.2 +/- 0.4. CONCLUSIONS As indicated by our small and early patient cohort left atrial cryoablation with the Surgifrost argon cryocatheter is effective for the treatment of atrial fibrillation. This new device is technically easy to handle, it can be applied through a median sternotomy or lateral minithoracotomy. Long-term follow-up is necessary to evaluate further rhythm outcome.

Computer-Enhanced Mitral Valve Surgery: Toward a Total Endoscopic Procedure

The aim of the study was to develop a computer-enhanced, video-assisted approach for mitral valve repair as a potential step toward a complete endoscopic procedure. In 10 patients with nonischemic mitral valve insufficiency, computer-enhanced telemetric mitral valve repair using the Intuitive surgical telemanipulation system was performed. A femorofemoral bypass was initiated using Port-Access (Heartport, Redwood City, CA) cannulation. A small minithoracotomy was made in the right 4th intercostal space, and a custom-made rib retractor was placed. The pericardium was opened manually, and four traction stay sutures were placed to enhance exposure. After endoaortic balloon clamping, the left atrium was opened and stabilized. The end-effectors were placed in the left atrium through two ports (3rd ICS and 6th ICS, midaxillary line). A 30 degrees three-dimensional (3D)-videoscope angled up was placed through the incision. Mitral valve repair was then performed remotely from the surgical console. This included inspection of the valve, leaflet resection, leaflet repair, and ring implantation. After completion of the repair and testing of the valve, the end effectors were withdrawn, and the left atrium was closed manually using standard endoscopic instruments (Heartport). In all but 1 patient, successful repair, including quadrangular resection, chordal shortening, Whooler-plasty, and Alfieri-plasty, could be accomplished using the computer-enhanced telemanipulation system. A partial ring was implanted in 6 patients and a complete ring was implanted in 3 patients, respectively. Time for surgery, CPB, and clamp time were 170 to 330 minutes (median, 185 minutes), 140 to 220 minutes (median, 149 minutes), and 78 to 133 minutes (median, 94 minutes), respectively. In one patient, intraoperative transesophageal echocardiography (TEE) showed insufficient repair, a second surgery was performed via an enlarged left thoracotomy. One patient with recurrent mitral insufficiency had to have a second surgery on postoperative day 3 for a torn-out ring. Median time of hospitalization was 8 days. At 3 months follow-up (completed in 7 patients), all patients had improved clinically. Computer-enhanced mitral valve repair is feasible and can be performed with good functional results. The telemanipulation system offers the potential for true endoscopic mitral valve repair. However, surgical time is prolonged, and a learning curve has to be overcome.

Transmyocardial laser revascularization with the holmium:YAG laser: loss of symptomatic improvement after 2 years

OBJECTIVE Whether transmyocardial laser revascularization (TMLR) provides a long-term benefit in terms of relief of angina, improvement of exercise tolerance, left ventricular function, and myocardial perfusion. METHODS Forty-one patients underwent TMLR using a holmium:YAG-laser, 14 as TMLR alone (group A), 27 with additional aortocoronary bypass grafting (group B). Follow-up was obtained at 6, 12, 18, 24, and 36 months in this prospective study. RESULTS In group A patients CCS-class improved up to 18 months postoperatively, after 24 and 36 months postoperatively there was absence of a positive effect of TMLR: the CCS-class decreased to 2.4 as compared to 3.5 preoperatively After combined CABG and TMLR (group B) there was a significant decrease in angina at all times. The CCS-functional class in these patients was 1.7 at 36 months as compared to 3.5 preoperatively. There was no significant change in exercise tolerance as compared to preoperatively. Left ventricular ejection fraction did not improve in either of the groups. Thallium scintigraphy indicated no improvement in myocardial perfusion in laser treated areas. The perioperative mortality was 0%, the late mortality rate was 36% in group A and 11% in group B. CONCLUSIONS In our experience, in the vast majority of patients who are subjected to TMLR alone the benefit of reduction or relief of angina and improvement in quality of life is only temporary. In addition there is no improvement in objective clinical parameters. We believe that TMLR should only be used in patients with severe angina refractory to medical treatment and requiring a symptomatic therapy.

Endoaortic Clamping Does Not Increase the Risk of Stroke in Minimal Access Mitral Valve Surgery: A Multicenter Experience

BACKGROUND Some controversy exists regarding the safety of endoaortic balloon clamping in minimal access isolated mitral valve surgery (MIMVS). The aim of this European multicenter study was to analyze the results in 10 experienced centers and compare the outcomes with published data. METHODS The most recent 50 consecutive MIMVS cases from 10 European surgeons who had performed at least 100 procedures were prospectively collected and retrospectively analyzed. All procedures were performed through right minithoracotomy with femoral cannulation and endoaortic balloon occlusion. In-hospital and 30-day outcomes were studied. Mortality and stroke rates were compared with published median sternotomy and MIMVS outcomes. RESULTS Mean age was 63.2 ± 12.5 years, 289 (57.8%) were male, mean logistic European system for cardiac operative risk evaluation was 6.1 ± 6.2, and 53 (10.6%) procedures had cardiac reoperations. Concomitant procedures were performed in 126 (25.9%) cases. Three patients (0.6%) required conversion to full sternotomy. Ten patients (2.0%) necessitated endoaortic balloon clamping conversion (8 to external clamping), and re-exploration for bleeding was necessary in 24 (4.8%) cases. Mean aortic cross-clamp and cardiopulmonary bypass times were 85.6 ± 30.1 and 129.5 ± 40.2 min, respectively, and were significantly longer for concomitant procedures (p < 0.001). There were no aortic dissections and no deep venous thromboses. Operative mortality (none neurologic) and major stroke occurred in 7 (1.4%) and 4 (0.8%) patients, respectively. These rates compared favorably with the published literature on isolated primary mitral valve surgery (MVS) through sternotomy or minithoracotomy (mortality rates 0.2% to 11.6%, stroke rates 0.6% to 4.4%). CONCLUSIONS Once procedural proficiency is acquired, endoaortic balloon clamping in MIMVS is a safe and effective technique. Despite the fact that this patient cohort also includes combined and redo procedures, the observed mortality and stroke rate compared favorably with the existing literature on primary isolated mitral valve surgery irrespective of the approach.

Cross-sectional survey on minimally invasive mitral valve surgery

BACKGROUND Minimally invasive mitral valve surgery (MIMVS) has become a standard technique to perform mitral valve surgery in many cardiac centers. However, there remains a question regarding when MIMVS should not be performed due to an increased surgical risk. Consequently, expert surgeons were surveyed regarding their opinions on patient factors, mitral valve pathology and surgical skills in MIMVS. METHODS Surgeons experienced in MIMVS were identified through an electronic search of the literature. A link to an online survey platform was sent to all surgeons, as well as two follow-up reminders. Survey responses were then submitted to a central database and analyzed. RESULTS The survey was completed by 20 surgeons. Overall results were not uniform with regard to contraindications to performing MIMVS. Some respondents do not consider left atrial enlargement (95% of surgeons), complexity of surgery (75%), age (70%), aortic calcification (70%), EuroSCORE (60%), left ventricular ejection fraction (55%), or obesity (50%) to be contraindication to surgery. Ninety percent of respondents believe more than 20 cases are required to gain familiarity with the procedure, while 85% believe at least one MIMVS case needs to be performed per week to maintain proficiency. Eighty percent recommend establishment of multi-institutional databases and standardized surgical mentoring courses, while 75% believe MIMVS should be incorporated into current training programs for trainees. CONCLUSIONS These results suggest that MIMVS has been accepted as a treatment option for patients with mitral valve pathologies according the expert panel. Initial training and continuing practice is recommended to maintain proficiency, as well as further research and formalization of training programs.

Anabolic steroids (metenolone) improve muscle performance and hemodynamic characteristics in cardiomyoplasty

The loss of force and mass in the conditioned latissimus dorsi muscle are principal reasons for the poor improvement in hemodynamic functioning attained by cardiomyoplasty. Using 24 sheep, we investigated the effect of anabolic steroids on the hemodynamic, histologic, and myophysiologic characteristics in the setting of cardiomyoplasty. In 12 of the animals (group A), the latissimus dorsi muscles were electrically conditioned with an Itrel pulse generator; in the remaining 12 animals (group B), the electrical conditioning was combined with the administration of an anabolic hormone (metenolone; 100 mg/week). The hemodynamic measurements were performed during isolated perfusion of the subclavian artery (maintenance of pressure in the muscles), while all other circulation variables were held at the exact and reproducible value of zero by inducing ventricular fibrillation. Maximum force and muscle mass showed a significant increase in group B (maximum force: group A, 4.23 +/- 0.55 kp, and group B, 6.0 +/- 3.14 kp; muscle mass: group A, +11.07% +/- 1.06%, and group B, +79.9% +/- 40.8%). The ratio of type I to type II fibers after 12 weeks was 65.2% to 34.8% in group A and 96.7% to 3.3% in group B, as opposed to 19.9% to 80.1% in the control group. No side effects of the anabolic steroids were observed during the experiment. In the hemodynamic studies, we were able to demonstrate a further significant increase in the left ventricular pressure, fractional fiber shortening value, ejection fraction, stroke volume, cardiac output, and stroke work when using conditioned latissimus dorsi muscles that were additionally treated with metenolone.(ABSTRACT TRUNCATED AT 250 WORDS)

Fibroelastoma of the aortic valve causing drop attack

A 77-year-old healthy woman presented with a drop attack. Transesophageal echocardiography clarified the diagnosis of a mobile pedunculated mass adjacent to the free margin of right coronary cusp of the aortic valve near the commissure between the right and the acoronar cusp with the tendency to prolaps into the right coronary ostium as the cause for the patient’s symptoms (Fig. 1). Complete surgical removal of the tumor was possible without replacement of the aortic valve. Histologic investigation revealed the diagnosis of a papillary fibroelastoma (Fig. 2).

Mid-term results of endoscopic mitral valve repair in combination with endocardial or epicardial ablation.

OBJECTIVE Concomitant ablative therapy for atrial fibrillation can be effective at converting patients to normal sinus rhythm and at maintaining a regular rhythm for at least 5 years. We provide herein a comparison of an endocardial approach using Cryoablation with an epicardial approach using a suction-based RF ablation technology. METHODS Between February 2004 and January 2009, 325 patients underwent an endoscopic mitral valve repair. Of those patients, 112 (35%) had a history of atrial fibrillation prior to the procedure, all of whom underwent a concomitant ablation procedure. The first group of 78 concomitant ablation patients underwent a left-sided endocardial ablation procedure using a Cryoablation device. The second group of 34 ablation patients underwent a left-sided epicardial ablation procedure using an internally cooled monopolar RF device. No significant differences existed between groups in the preoperative data. All ablated patients were treated by the same Amiodarone protocol. Patients were followed for a minimum of 6 months for determining each ablated patients rhythm, medication use, and overall health status. RESULTS The AF-free rates of group I and group II patients were statistically equivalent for both ablation groups at all evaluation time points. None of the 112 patients treated with endoscopic mitral valve repair and ablative therapy experienced a specific patient injury attributable to ablation; no ablated patients died in hospital following the procedure; there were no esophageal perforations and no coronary artery stenosis due to the ablations in either ablation group. The rate of patients without AF was 74% in group I and 82% in group II in the 6-month follow-up. The group I pacemaker implantation rate of 14% was significantly higher than non-ablated group (4.7%), but the group II rate of 5.9% observed did not differ significantly from the non-ablated group. CONCLUSIONS It was shown with our results that one succeeds with the en bloc-ablation in treating patients with different kinds of atrial fibrillation with concurrent intervention in the mitral valve reliably and with a high rate. The combination of this procedure with endocardial interventional ablation technologies can possibly develop to a promising strategy in the hybrid therapy of the isolated chronic atrial fibrillation as a standalone procedure.

Die chirurgische Behandlung des therapierefraktären Vorhofflimmerns

Atrial fibrillation in patients with isolated, therapy resistant, chronic or paroxysmal atrial fibrillation (AF) or AF in combination with additional valvular and non-valvular cardiac pathology can be surgically treated by different techniques. Unipolar high frequency, cryotherapy and microwave energy is a curative approach for the treatment of the left atrium for AF. The postoperative mortality and morbidity rate is comparable to other cardiac surgery procedures. It is a technically less challenging procedure as compared to the MAZE procedure and can be applied using a minimally invasive approach. Alternative techniques such as new cryotechnologies, laser application and bipolar high frequency energy need to be evaluated for effectiveness and safety. Patienten mit alleinigem therapierefraktärem chronischen oder paroxysmalen Vorhofflimmern, oder mit begleitenden kardialen Erkrankungen, wie Herzklappendegenerationen, können mit verschiedenen Techniken chirurgisch behandelt werden. Mit der unipolare Hochfrequenzenergie, der Kryoapplikation und der Mikrowellenenergie ist eine erfolgreiche Behandlung des Vorhofflimmerns im Bereich des linken Vorhofes möglich. Die postoperative Mortalität und Morbidität ist vergleichbar mit anderen kardiochirurgischen Eingriffen. Der operative Eingriff ist weniger aufwendig als die MAZE-Operation und kann in einer minimalinvasiven Technik, auch in Zusammenhang mit Mitralklappeneingriffen, durchgeführt werden. Alternative Techniken, wie die neue Kryotechnologien, die Laserapplikation und die bipolare Hochfrequenzenergie werden im Rahmen von Studien auf ihre Effektivität und Sicherheit geprüft.