ABC | Volume 115, Nº2, August 2020

Original Article Gatti et al. Custodiol®-HTK solution & prolonged cross-clamp time Arq Bras Cardiol. 2020; 115(2):241-250 shown similar clinical outcomes for the two options. 5,7,8,17,19 Actually, only few studies have shown some benefits deriving from either one of the two cardioplegic strategies. For example, lower values of cardiac troponin I for XCT >160 minutes have been reported for Custodiol-HTK patients undergoing aortic surgery by Scrascia et al. 4 . Prathanee et al. 12 have stigmatized that using Custodiol-HTK cardioplegia in isolated coronary surgery leads to a significantly increased risk of spontaneous ventricular fibrillation after releasing of the aortic clamp. However, no clinical significance has been given to this fact. Very recently, in a series of 362 patients who underwent (minimally invasive or open) heart valve surgery, Hummel et al. 20 have shown superior outcomes for Custodiol-HTK patients as to blood transfusion, stroke and 30-day hospital readmission from discharge, this translating in an average hospital net savings of about $3,000 per patient. Finally, equivalent outcomes between Custodiol-HTK and cold blood cardioplegia have been shown by Hoyer et al. 11 for 825 pairs of propensity score-matched patients, even though blood cardioplegia seemed to be beneficial in the presence of left ventricular dysfunction. Because a single-dose of Custodiol-HTK cardioplegia is claimed to offer prolonged myocardial protection, 2,3 during the study period it was generally used, in coronary surgery, for patients with expected long time of surgery (high number of coronary anastomoses, low diameter of the coronary vessels, intramyocardial course, multiple and distal lesions, need for endarterectomy, diffuse coronary calcification, …). This fact may explain both the very long operation times and the high rate (about 36%) of HTK patients who were enrolled in the present study. It should also be emphasized that every proximal anastomosis between the aorta and venous graft was performed during aortic cross-clamping. The primary limitations of this single-center study were its retrospective nature and the fact that outcomes of a limited series of patients were investigated. Only early outcomes were reviewed and neither late outcomes post-surgery nor coronary angiographic results were explored. Consequently, the results obtained can in no way be considered conclusive and should be verified in larger patient populations by means of randomized controlled trials. Conclusions Based on the results of the present study, there was no significant difference in myocardial protection between Custodiol-HTK and MCB cardioplegia. However, outcomes of isolated coronary surgery requiring prolonged XCT seemed to be poorer using Custodiol-HTK solution rather than MCB cardioplegia. Although differences in postoperative fluid balance and renal function seemed to be involved, several variables might have interfered in the outcomes, which Table 2 – Operative data* Data Overall series PS-matched pairs HTK cohort n=38 MCB cohort n=110 p-Value Standardized difference HTK cohort n=34 MCB cohort n=34 p-Value Standardized difference No. of coronary anastomoses 5.2±1.3 4.6±1 0.003 5.1±1 5.2±1 0.481 Grafting 0.249 0.510 Bilateral ITA 30 (78.9) 97 (88.2) 27 (79.4) 30 (88.2) Single ITA 8 (21.1) 12 (10.9) 7 (20.6) 4 (11.8) SVGs alone 0 1 (0.9) 0 0 XCT, min 136 (128−148) 130 (124−139) 0.031 137 (128−148) 135.5 (125.5−145.5) 0.971 120–149 29 (76.3) 97 (88.2) 0.001 26 (76.5) 27 (79.4) 0.000 150–179 8 (21.1) 10 (9.1) 0.022 8 (23.5) 5 (14.7) 0.002 180–209 0 3 (2.7) 0.050 0 2 (5.9) 0.007 >209 1 (2.6) 0 - 0 0 - Spontaneous VT/VF after 2 (5.3) 12 (10.9) 0.362 0 0 - cross-clamp releasing CPB time (min) 234 (217−259) 225 (209−253) 0.193 224.5 (216−252) 234.5 (222−261.5) 0.464 Length of operation (min) 345 (326−389) 340 (315−369) 0.412 341 (326−378.5) 338 (320−366.5) 0.962 Total fluid balance/BSA (ml/m 2 ) +2900 (2440−3590) +2440 (2030−3140) 0.003 +2860 (2440−3660) +2500 (2000−3030) 0.013 *Continuous variables were expressed as mean ± SD, or median and the range between the first and the third quartile. Categorical variables were expressed as frequencies and percentages. BSA: body surface area; CPB: cardiopulmonary bypass; HYK: histidine-tryptophan-ketoglutarate; ITA: internal thoracic artery; MCB: multidose cold blood; PS: propensity score; SD: standard deviation; SVG: saphenous vein graft; VT/VF: ventricular tachycardia/fibrillation; XCT: cross-clamping time. 245