Christoph Lutz

Transmyocardial laser revascularization (TMLR) in patients with unstable angina and low ejection fraction

OBJECTIVE Does perioperative use of the intraaortic balloon pump (IABP) improve the postsurgical outcome of patients presenting with endstage coronary artery disease, unstable angina and low ejection fraction transferred for transmyocardial laser revascularization (TMLR)? METHODS TMLR, as sole therapy combined with the perioperative use of an intraaortic balloon pump has been assessed in seven patients with endstage coronary artery disease, unstable angina and low ejection fraction (EF < 35%). Six out of seven patients had signs of congestive heart failure. These patients are compared with 23 patients with endstage coronary artery disease, stable angina and EF > 35%, who were treated with TMLR as sole therapy without the use of IABP. The creation of transmural channels was performed by a CO2-laser. All patients were evaluated by hybrid positron emission tomography (perfusion SPECT and viability PET) and ventriculography preoperatively. Echocardiography, clinical status and hemodynamic assessment by Swan Ganz catheter were performed perioperatively. RESULTS The perioperative mortality of this combined procedure (TMLR and IABP) was zero. Three out of seven patients had pneumonia with complete recovery. Swan Ganz catheter examinations showed deterioration of LV-function after TMLR intraoperatively and improvement after 2 h and further after 6 h on ICU (P < 0.05). In contrast, a decrease of LV-function in sole TMLR patients with an EF > 35%) has not been observed. Patients with EF < 35% needed the IABP for 2.3 days and moderate dose catecholamines for a mean of 3.0 days. The postoperative EF and resting wall motion score index (WMSI) of all analysed LV segments (evaluated by echocardiography) did not change compared to baseline (EF 31.3+/-2.6 preop. to 32.8+/-3.2 postop.; WMSI: 1.75+/-0.14 at baseline to 1.71+/-0.17 postop.). The average Canadian Angina Class at the time of discharge decreased from 4.0+/-0 (baseline) to 2.3+/-0.5 (P < 0.05) and the NYHA-Index from 3.9+/-0.3 to 2.7+/-0.5. No patient had signs of angina pectoris, whereas two patients still had signs of congestive heart failure. CONCLUSIONS The reported data support our concept to start IABP preoperatively in patients with reduced LV contractile reserve in order to provide cardiac support during the postoperative phase of reversible decline of LV-function induced by TMLR.

Histologic findings of transmyocardial laser channels after two hours

Histologic examination of the human myocardium has been performed several days, weeks, and months after transmyocardial laser revascularization. We performed microscopic examinations 2 hours postoperatively. In addition to the patent channel (diameter, 1 mm) and a 1-to 2-mm rim of necrosis, a 1- to 3-mm zone of myofibrillary degeneration was found. This additional reversible injury immediately after transmyocardial laser revascularization could explain the higher mortality rate in patients with reduced left ventricular function.

Transmyocardial laser – revascularization: experimental studies on prolonged acute regional ischemia

OBJECTIVE This experimental study in pigs was undertaken to answer the question whether TMLR after acute myocardial infarction may improve regional myocardial perfusion, left ventricular function and diminish myocardial necrosis in the area at risk. METHODS Thirty open-chest anesthetized pigs were observed for 6 h, six pigs served as controls. In 24 pigs, occlusion of the left anterior descending artery (LAD) beyond the first diagonal branch was performed: seven pigs had LAD occlusion only (ischemia group), and 17 pigs were treated by TMLR (using a CO2-laser, energy: 40 J) prior to coronary occlusion; nine pigs received one laser channel (1 mm diameter) per cm2 (laser group 1) and eight pigs two channels per cm2 in the LAD territory (laser group 2). Regional myocardial blood flow by microspheres, function (franc starling curves), histochemical assessment (triphenyl tetrazolium chloride, TTC and histology), were performed. RESULTS The lased pigs were less prone to ventricular fibrillation (laser group 2, 38%; laser group 1, 56%; ischemic group, 100%; P < 0.05), and showed a significant smaller area of necrosis (TTC) in the area at risk (laser group 1, 23%; laser group 2, 14%; vs. ischemia group, 31%; P < 0.01). There was no significant difference between laser-treated and ischemia hearts regarding the amount of blood flow into the infarcted LAD region and the maximal left ventricular stroke work index after 6 h (P = n.s). Regional myocardial blood flow: ischemia group, 4 +/- 5 ml/100 g/min; laser group 1, 3 +/- 10 ml/100 g/min, and laser group 2, 2 +/- 10 ml/100 g/min; maximal left ventricular stroke work index: ischemia group, 1.8 mJ/g; laser group 1, 2.1 mJ/g and laser group 2, 2.1 mJ/g. CONCLUSIONS This model of acute regional ischemia demonstrates that CO2-laser revascularization diminish significantly the incidence of ventricular fibrillation and necrosis in the area at risk, and does not change regional myocardial perfusion and global left ventricular function. This experiment indicates that TMLR may be an alternative in treating advanced ischemic heart disease.

Minimal-invasive, video-assisted vein harvesting for cardiac and vascular surgical procedures.

Harvesting of the saphenous vein is a routine procedure in coronary and peripheral vascular surgery. It is usually performed using a continuous long skin incision. Minor complications are reported in up to 24% (hematoma, wound dehiscence, infection, pain) and major problems necessitating surgical interventions (bleeding, abscess) in less than 1%. These complications lead to a prolonged hospital stay. To reduce these complications we have used a new endoscopic, video-assisted technique in 17 patients. Harvesting of the total length of the saphenous vein is possible with only one 2-3 cm long incision proximally the knee joint. We conclude that this technique is safe, may reduce the morbidity of saphenous vein harvesting and is associated with a perfect cosmetic result.

Behandlungsstrategien bei therapierefraktärer Angina pectoris: Transmyokardiale Laserrevaskularisation

Hintergrund: Vermag die Transmyokardiale Laserrevaskularisation (TMLR) als eine neue chirurgische Methode zur Behandlung der schweren Angina pectoris die myokardiale Perfusion und Kontraktilität zu verbessern?¶Methoden: Siebenundsechzig Patienten, die zur TMLR überwiesen worden waren, wurden mittels klinischer Untersuchung, Ergometrie, Echokardio-, Ventrikulographie und hybrid PET präoperativ und Patienten, die mit TMLR behandelt wurden, nach 6 und 12 Monaten follow up evaluiert. Hämodynamische Messungen und klinische Untersuchung wurden perioperativ durchgeführt.¶Ergebnisse: In 28 von 67 Patienten (42%) ACVB, in 9 von 67 Patienten (13%) ACVB in Kombination mit TMLR (kombinierte Gruppe) und in 30 von 67 Patienten (45%) nur TMLR (isolierte Gruppe) wurden durchgeführt. Die perioperative Letalität in der isolierten Gruppe lag bei 13%, in der kombinierten Gruppe bei null und in der ACVB Gruppe bei 11%. In jeder Gruppe wurde ein signifikant verbesserter klinischer Status (p≤0,01) 1 Woche postoperativ und in den TMLR-Gruppen auch nach 6 und 12 Monaten beobachtet. In den TMLR-Gruppen verbesserte sich ebenfalls die Belastbarkeit in der Ergometrie (p<0,05), obgleich Funktion, Perfusion und Metabolismus sich nach 6 und 12 Monaten follow up nicht signifikant veränderten.¶Zusammenfassung: TMLR verbessert signifikant den klinischen Status und die Belastbarkeit in der Ergometrie, aber verändert nicht die Perfusion, Funktion und den Metabolismus. Background: Does transmyocardial laser revascularization (TMLR) as a new surgical technique for treating patients with otherwise intractable angina pectoris improve myocardial perfusion or contractility? Methods: Sixty-seven patients transferred for TMLR were evaluated by clinical evaluation, treadmill stress testing, echocardiography, ventriculography, and hybrid positron emission tomography preoperatively and in patients treated with TMLR at 6 and 12 month follow up. Hemodynamic assessment and clinical evaluation were performed perioperatively. Results: In 28/67 cases (42%) CABG, in 9/67 patients (13%) CABG in combination with TMLR (combined group), and in 30/67 patients (45%) only TMLR (sole group) were performed. Perioperative mortality in the sole group was 13%, in the combined group zero, and in the CABG group 11%. In all groups a significantly improved clinical status (p≤0.01) 1 week postoperatively and in TMLR groups also at 6 and 12 months was observed. In the TMLR groups treadmill tolerance (p<0.05) improved, although function, perfusion and metabolism did not change significantly at the 6 and 12 month follow up. Conclusion: TMLR significantly improves clinical status and treadmill stress tolerance, but does not change function, perfusion, and metabolism.

A retrospective audit of long-term lower limb complications following leg vein harvesting for coronary artery bypass grafting

We would like to congratulate Dr Garland and colleagues for their important and honest paper concerning the incidence of lower limb complications following leg vein harvesting for coronary artery bypass grafting (CABG) [1]. They have described clearly the high incidence of wound infections, numbness, pain and unilateral leg swelling after conventional vein harvesting for CABG. In addition, the authors could not confirm the previously reported association to risk factors by other groups, such as diabetes or peripheral vascular disease. Garland et al. [1] also point to the fact that most of the wound infections occur following hospital discharge and are associated with a high rate of postoperative antibiotic use. The rate of wound infection after vein harvesting is even higher in patients with vascular operations (17–44%) [2]. Even though arterial conduits are increasingly used, at least one vein is still harvested in the majority of CABG procedures worldwide. Given the good shortand long-term results of surgical revascularization for patients with coronary artery disease, problems at the leg vein harvesting site are often the major complaint of the patients after these procedures. Major efforts are being undertaken to reduce the size of the chest incision (half sternotomy, lateral thoracotomy, usage of ports), even though the complication rate from a sternal incision is relatively low. Therefore, every effort should be undertaken to reduce the complications from the conventional vein harvesting procedures, which are described by Garland et al. [1]. With the current availability of the minimally invasive, endoscopic vein harvesting procedure, a solution to this postoperative complication seems to be realistic. The authors have pointed to this technique in their report and have also listed potential drawbacks of this method, such as increased harvest time, additional expense and potential for vein trauma [1]. Our group [3,4] as well as many others have shown the significant advantages of this technique as compared to the conventional procedure in terms of wound infections, neuropathy, pain, swelling as well as patient comfort and satisfaction. We are using this method for 7 years and this has resulted in an almost complete disappearance of any leg wound complications. Currently all veins in all patients are harvested with this method with a very low rate of contraindications. Our group has developed a non-disposable, minimal-invasive, endoscopic harvesting system (Vein harvesting system Freiburg, Storz Co., Tuttlingen, Germany) which needs only one 3–4 cm, horizontal skin incision medially above the knee for harvesting the entire saphenous vein from the ankle to the groin. Harvest time is no longer prolonged as compared to the conventional method and is sometimes even faster. The learning curve is approximately 2 months and this method is now performed by all surgical assistants after their 2nd or 3rd year of training. The costs are reduced to the one-time purchase of the endoscopic system. The vein harvesting system is nondisposable. The potential for endothelial trauma has been addressed by us as well as by others [5]. There has been no report of any additional damage to the vein endothelium as compared to the conventional technique. In summary, minimally-invasive endoscopic vein harvesting is able to reduce significantly the well known and by Garland et al. reported complications of vein harvesting and should be used routinely. Garland and co-workers are to be congratulated for their study and for emphasizing again the importance of this aspect of CABG.