Video-assisted thoracoscopic implantation of the left ventricular pacing lead for cardiac resynchronization therapy.

BACKGROUND: To study the feasibility and efficacy of video-assisted thoracoscopic (VAT) placement of the left ventricular pacing lead for cardiac resynchronization therapy (CRT) where the conventional transvenous coronary sinus approach has failed. METHODS: Seventeen patients underwent the VAT procedure. Indications for CRT were ischemic cardiomyopathy in six patients and nonischemic cardiomyopathy in 11. The procedure was performed under general anesthesia with single-lung ventilation. Three 2-cm incisions were used on the left chest wall to place the screw-in lead near the obtuse marginal arteries high on the lateral wall of the left ventricle (LV). RESULTS: The VATS approach was successful in 13/17 (76%) patients. Median procedure time was 75 minutes (range 55-135). A learning curve was observed that appeared to plateau at 75 minutes procedure time after four cases. Median length of hospital stay was 2 days (range 2-8) with one patient requiring intensive care. Satisfactory thresholds and impedances of 2.3 +/- 0.9 V/0.5 ms and 560 ohms, respectively, were achieved at mean follow-up of 226 days. All patients reported symptomatic benefit with reduction in New York Heart Association score from III preoperatively to II postoperatively. CONCLUSIONS: VAT placement of the epicardial pacing lead is feasible, safe, and efficacious. It should be considered in cases where the transvenous route has failed or as an alternative in prolonged or hazardous transvenous procedures.

Beating-heart mitral valve surgery in patients with poor left ventricular function.

BACKGROUND AND AIM OF THE STUDY: Mitral valve surgery in the presence of poor left ventricular (LV) function is associated with higher mortality. One surgeon's (S. K. N.) evolving practice of mitral valve surgery on the beating heart using normothermic cardiopulmonary bypass (CPB) in a cohort of patients is described. METHODS: Between July 2000 and December 2002, 23 patients (13 men, 10 women; mean age 68.6 +/- 4.8 years; range: 54-81 years) with mitral regurgitation and LV ejection fraction <30% undergoing isolated mitral valve repair (n = 4) or replacement (n = 19) were investigated. All patients received maximal drug therapy. Among patients, 17 were in NYHA class III, and six in class IV. RESULTS: The mean duration of follow up was 17 +/- 14 months, and was complete for all survivors. The visual field of the on-pump beating heart was equal to that of conventional valvular surgery, and technical accuracy was not compromised. The mean ICU and hospital stays were 2.4 +/- 1.3 days and 8.9 +/- 2.6 days, respectively. Mean CPB time was 74.3 +/- 14.8 min. Thirty-day mortality was significantly lower (8.7%) when compared to mean Euroscore-predicted mortality for this high-risk group (16.9%; p <0.001). The medium-term one- and two-year survivals were 87% and 78%, respectively. Mean NYHA class was improved, from 3.6 +/- 0.5 preoperatively to 1.9 +/- 0.7 at follow up (p = 0.037). CONCLUSION: On-pump, beating-heart mitral valve surgery is a good option in patients with poor LV function, and is advantageous as conditions for the heart are more physiological with a beating tonus than with cardioplegia.

Simple technique of talc delivery for video-assisted talc pleurodesis.

It has been proven that talc is the sclerosant of choice for pleurodesis, especially for malignant effusions. Uniform talc deposition on the visceral pleura is often difficult, resulting in clump deposition with the use of an atomizer or bladder syringe delivery apparatus. We have devised a simple sterile apparatus that allows the operator to retain full control over the talc delivery rate and coat the lung uniformly under direct vision using a pressurized system.

Unusual case of two synchronous intracavitary primary cardiac tumors.

We report a patient who had two histologic and distinct synchronous intracardiac tumors, with one located in each atrium. The second tumor was missed on intraoperative transesophageal echocardiography, but was discovered when the right atrium was opened using a bi-atrial trans-septal approach. We discuss the merits of this approach and the role of additional imaging for cardiac tumors.

Management of acute coronary syndrome.

This is a review of acute coronary syndrome as a clinical entity. An appreciation of acute coronary syndrome as a disease spectrum is presented along with contemporary evidence for its diagnosis and approach to medical and surgical management.

How I do it: transapical cannulation for acute type-A aortic dissection.

Aortic dissection is the most frequently diagnosed lethal disease of the aorta. Half of all patients with acute type-A aortic dissection die within 48 hours of presentation. There is still debate as to the optimal site of arterial cannulation for establishing cardiopulmonary bypass in patients with type-A aortic dissection. Femoral artery cannulation with retrograde perfusion is the most common method but because of the risk of malperfusion of vital organs and atheroembolism related to it different sites such as the axillary artery, the innominate artery and the aortic arch are used. Cannulation of these sites is not without risks of atheroembolism, neurovascular complications and can be time consuming. Another yet to be popularised option is the transapical aortic cannulation (TAC) described in this article. TAC consists of the insertion of the arterial cannula through the apex of the left ventricle and the aortic valve to lie in the sinus of Valsalva. Trans-oesophageal guidance is necessary to ensure correct placement of the cannula. TAC is an excellent method of establishing cardiopulmonary bypass as it is quick, provides a more physiological method of delivering antegrade arterial flow and is the only method to assure perfusion of the true lumen.

Should we perform preoperative coronary angiography in all cases of atrial myxomas?

The prevalence of coronary disease is high in patients with atrial myxomas yet routine angiography is not performed. Moreover, some tumors have angiographically detectable neovascularity, which can alter surgical planning. We report two cases that support our recommendation for performing coronary angiography in all cases diagnosed with cardiac myxomas.

Strength of wired sternotomy closures: effect of number of wire twists.

The objective of this study was to investigate the effect of the number of wire twists on the strength of wired sternotomy closures. A custom-built test rig, fitted to a materials testing machine, was used to apply an increasing tension to wire closures, until they failed. The number of twists in the wire closure was varied between one and ten. Stainless steel wires of diameter 0.7 mm (No. 5) and 0.9 mm (No. 7) were tested. Initially, there is an increase in the maximum strength of the wire closure with increasing number of wire twists. After three wire twists greater strength is not achieved with increasing the number of wire twists. The highest mean force taken by the 0.7 mm diameter wire was 613 N (approximately 63 kg), at nine wire twists, whereas the highest force taken by the 0.9 mm diameter wire was 887 N (approximately 90 kg), at eight wire twists. However, by three wire twists, 80% and 88% of the maximum force has been achieved for the 0.7 and 0.9 mm diameter wire, respectively. Twisting wires many times in a sternotomy closure does not result in increased strength. Three or four twists would appear sufficient to sustain the forces across a sternotomy.

Sternum screw: analysis of a novel approach to the closure of the chest after surgery.

BACKGROUND: To show the benefits of using a novel approach to closure of the median sternotomy through a mechanical model and mechanical testing. Simple cannulated screws are placed on either side of the sternotomy. Conventional stainless steel wire is passed through the cannula of each screw and the sternotomy is closed in the usual manner. METHODS: Hertzian contact analysis was used to estimate the stress between the wire and the sternum. Mechanical testing was used to compare using wire on its own with a sternum screw plus wire. Ten samples of balsa wood (sternum substitute) had wire placed through a hole in them, while a further ten samples were fitted with a cannulated screw and had wire passed through the screw cannula. The wire was connected to a materials testing machine, which applied tension to the wire until the wire or screw cut through the wood. RESULTS: The analysis showed that the mean stress between the wire and the sternum decreases with increasing wire diameter. At low diameters of wire the stress in the sternum can be comparable to the failure stress of bone. Using a cannulated screw reduces the stresses in the sternum. The mechanical testing showed that the wire cut through the wood at a mean load of 104 N, whereas the sternum screw cut through the wood at a mean load of 209 N (p = 0.007, Mann-Whitney Test). CONCLUSIONS: Closing a median sternotomy with cannulated screws plus wire should reduce the occurrence of sternal dehiscence.

Preliminary evaluation of the Sternum Screw: a novel method for improved sternal closure to prevent dehiscence.

Sternal dehiscence is a relatively rare but serious complication of sternal closure with an unacceptable mortality and morbidity rate. The 6 mm cannulated Sternum Screws are a novel approach that aims to prevent dehiscence. The screws are placed on either side of the sternotomy and wire threaded through the cannula and closed customarily. The Sternum Screws make the bone non-penetrable at the same time retaining the familiarity of conventional stainless steel wire. This novel technique was tested in sheep sterna to compare its efficacy to conventional wire closure. Using tensile testing in a testing machine, randomised controlled closures of the Sternum Screws and No. 5 stainless steel wires were evaluated until system failure. Seventeen matched pairs were tested. The Sternum Screw closure was on average 36% stronger, 284+/-43 N (mean+/-SD) compared to conventional wire closure alone, 215+/-38 N (mean+/-SD) [p<0.0001 by t-test]. System failure in 82% of Sternum Screw closures, however, was due to wire breakage or untwisting rather than the screw itself. In all these cases the screw remained intact in bone. 71% of conventional wire closures failed by dehiscing through the sterna. The mean forces required for wire dehiscence and wire failure in the Sternum Screws may be achieved in vivo during large coughs. The study shows there is merit in further evaluating the approach as a method of preventing dehiscence. It also highlights the use of alternative wiring techniques increase the tensile strength of the closure yet retain the familiarity and versatility of conventional wire.