Modifications of the Cox-Maze III procedure

Background. The extended operative time needed for surgery With complicated atrial incisions may preclude application of the Cox-Maze III procedure (C M-III) as a concomitant operation. And after the CM-III, left atrial (LA) c ontraction has been reported to recover in reduced magnitude compared with right atrial (RA) contraction. Methods. To decrease operative time, we have modified the Chi-III (modifica tion I) by: obliterating the LA appendage instead of excising it; cryoablat ing the bridge between the LA appendage and margin of the pulmonary vein en circling incision; extending the lateral incision of RA onto the RA appenda ge without excising it, and extending the incision more inferiorly toward t he inferior vena cava; and omitting the T-incision of RA. We compared the c linical results of the conventional CM-III (group 1, n = 18) with those of the modified CM-III group (group 2, n = 23) performed in patients with rheu matic mitral valve (MV) disease. To enlarge the contractile area of the LA, we modified the CM-III to encircle the right and left pulmonary veins sepa rately (modification II), and compared the LA contractilities of the conven tional CM-III (group A, n = 15) with those of the second modification (grou p B, n = 9). Results. Modification I: Mean aortic cross-clamp (ACC) times (135 +/- 29 ve rsus 104 +/- 18 minutes, p < 0.005) and cardiopulmonary bypass (CPB) times (240 +/- 33 versus 185 +/- 42 minutes, p < 0.001) were significantly decrea sed in group 2 compared with those in group 1. In group 1, sinus rhythm was restored in 16 patients (88.9%). RA contractility was demonstrated in 100% of patients with sinus rhythm (16 of 16) and LA contractility in 75% (12 o f 16) in the latest follow-up echocardiography, In group 2, sinus rhythm wa s restored in 21 patients (91.3%). RA contractility was demonstrated in 100 % of patients with sinus rhythm (21 of 22) and LA contractility in 76.2% (1 6 of 21). Modification II: Mean ACC times Were increased in group B compare d with group A (133 +/- 32 versus 172 +/- 39 minutes, p = 0.02). The A velo cities at LA contraction and the ratio of atrial contraction to peak early diastolic filling velocity (A/E ratio) of the trans-mitral now were 0.14 +/ - 0.20 m/sec and 0.23 +/- 0.11 in group A, and 0.58 +/- 0.33 m/sec and 0.47 +/- 0.19 in group B, respectively, both showing a significant increase in group B compared with group A (p < 0.05). Conclusions. Our first modification of the Chi-III showed comparable sinus conversion rates and incidence of atrial contractility restoration with sig nificantly shorter ACC and CPB times than the conventional CM-III. The seco nd modification of the CM-III significantly increased the LA contractility when compared with the conventional Chi-III, although the second modificati on required a longer ACC time. (C) 2001 by The Society of Thoracic Surgeons .