Application of right atrial contiguous linear lesions: an in vivo efficacy validation of multipolar ablation catheters in an animal model.

Catheter ablation of atrial flutter and catheter Maze procedures require the creation of linear lesions. The efficacy of different multipolar catheters to create linear contiguous transmural lesions was studied in a sheep model. In 19 sheep a multipolar ablation catheter was inserted into the right atrium. In nine sheep a steerable 7 Fr catheter (C1) with six 6-mm electrodes and in five sheep a steerable 7 Fr catheter (C2) with four 5-mm electrodes were placed. In five sheep a 3.7 Fr catheter (C3) with eight electrodes of 6-mm length was deployed (steerable sheath). A total of 72 linear lesions were created and evaluated. Catheter types C1, C2, and C3 produced continuous lesions with at least two adjacent electrodes in 45%, 79%, and 87% of the lesions. The mean lesion length achieved by C3 was longer compared to C1 and C2 (27 +/- 14 vs 10 +/- 5 and 11 +/- 6 mm; P < 0.05). The ability to produce contiguous lesions by all available electrodes was low: C1, 5%; C2, 5%; and C3, 6%. C3 was most effective in exerting transmural lesions (93% vs C1 75% and C2 57%; P < 0.0001). Microscopic endocardial fibrinous adhesions and macroscopic mild electrode carbonizations were caused by all catheter types. In conclusion, (1) all three catheter types do not create contiguous lesions along all electrodes. Gaps of viable tissue remain in most instances; (2) lesion depths and transmurality varies with different catheters; and (3) potentially hazardous thrombotic material was observed during radiofrequency ablation with all three catheters.

Periarterial papaverine application improves intraoperative kidney function during laparoscopic donor nephrectomy.

BACKGROUND: Laparoscopic donor nephrectomy decreases disincentives to donation frequently associated with the disadvantages of open surgery. However, concerns have been raised regarding graft quality, since the incidence of delayed graft function is higher when compared with open procedures. This may be caused by amelioration of kidney perfusion due to the elevated intraabdominal pressure and to a mechanically induced renal angiospasm during donation. This study was addressed to reveal whether the renal periarterial application of papaverine is able to enhance renal blood flow during laparoscopic nephrectomy. MATERIALS AND METHODS: Twelve male piglets underwent left laparoscopic donor nephrectomy after endoscopic occlusion of the right renal vessels and ureter. Urine output and creatinine clearance were determined as indicators of renal blood flow. In the treatment group (n = 6) papaverine hydrochloride was administered to the tissue surrounding the renal artery prior to preparation of the vessels and results were compared with those of controls (n = 6). Free sodium excretion was measured to preclude prerenal failure. RESULTS: In the control group the mean urine output was 0.015 ml/min/kg and the mean creatinine clearance was 0.95 ml/min/kg. In pigs treated with papaverine the mean urine output was 0.052 ml/min/kg and the mean creatinine clearance was 2.22 ml/min/kg. The differences were significant (urine output, P = 0.02; creatinine clearance, P = 0.038). CONCLUSIONS: Papaverine improves renal function during laparoscopic kidney harvest when applied in the vicinity of the renal artery prior to vascular preparation.