Common use of Surgical procedures Clause in Contracts

Surgical procedures. The indication for surgery was assessed by the multidisciplinary Heart Team, consisting of cardiologists, cardiothoracic surgeons, imaging specialists, heart failure specialists, and anesthesiologists.25 All operations were performed through midline sternotomy using CPB, aortic cross-clamping, and intermittent antegrade warm blood cardioplegia. RMA was performed for moderate to severe functional MR in all patients. Ring size was determined by measuring the anterior leaflet height and then downsizing by 2 ring sizes using a semirigid annuloplasty ring (Physio ring, ▇▇▇▇▇▇▇ Life Sciences, Irvine, CA). RMA was considered successful in case no or mild MR and a leaflet coaptation height of ≥8 mm were observed on transoesophageal echocardiography. Tricuspid valve repair was performed with an annuloplasty ring (▇▇▇▇▇▇▇ Life Sciences MC3 ring or ▇▇▇▇▇▇▇ Physio Tricuspid) in patients with tricuspid regurgitation ≥ grade 3 or a tricuspid annular diameter ≥40 mm (or >21 mm/m2 body surface area). Concomitant implantation of a CorCap CSD (Acorn Cardiovascular, St. ▇▇▇▇, MN) was performed in patients with non-ischaemic heart failure and a preoperative left ventricular end-diastolic diameter ≥65 mm or indexed left ventricular end-diastolic diameter ≥30 mm/m2. The CSD is a passive external fabric mesh containment device that is implanted to reduce LV wall stress by providing circumferential diastolic support in order to prevent further LV remodelling. Concomitant myocardial revascularization was performed when indicated. Patients did not receive ACE inhibitors, ARBs, or diuretics on the day of surgery. Anaesthetics and haemodynamic monitoring Before induction all patients received an arterial catheter for invasive monitoring of blood pressure. A central venous catheter was inserted in the internal jugular vein and a flow-directed balloon-tipped pulmonary artery catheter (▇▇▇▇▇▇▇ LifeSciences, Irvine, CA) was introduced after induction for continuous monitoring of cardiac output and pulmonary artery pressure. These data were used to calculate the cardiac index and systemic vascular resistance. Norepinephrine, 0.04 to 0.2 µg/kg/min, was started when the mean arterial pressure was <65 mmHg and the cardiac index was normal (after adequate administration of intravascular fluids if necessary). The aim was for a mean arterial pressure >65 mmHg and adequate end-organ perfusion. When a norepinephrine dosage >1 µg/kg/min was required, terlipressin was started. Both norepinephrine and terlipressin were reduced when the mean arterial pressure was >65 mmHg and end-organ perfusion was restored. Statistical Analysis Continuous variables are expressed as mean ± standard deviation (SD) when normally distributed or otherwise as median and interquartile range (IQR). The normality of data distribution was determined graphically using the Q-Q plot and tested with the ▇▇▇▇▇▇▇-▇▇▇▇ Test of Normality. Categorical variables are presented as numbers and percentages. Missing values for cross clamp time (n = 2, 2%) were replaced using multiple imputations with predictive mean matching, which was repeated 100 times. Baseline age, gender, EuroSCORE, New York Health Association (NYHA) class, creatinine clearance, cross-clamp time, and procedure time were used as predictors in the model. The pooled data were used for analysis. Heart failure patients with ischaemic and non-ischaemic MR and vasoplegic and non-vasoplegic patients were compared. Comparison of continuous data was performed using 2-tailed unpaired Student’s t-test for normally distributed variables or otherwise the ▇▇▇▇-▇▇▇▇▇▇▇ U test. The ▇▇▇▇▇▇-▇▇▇▇▇ method was used to assess 30-day and 90-day survival in vasoplegic and non- vasoplegic patients; the analysis was repeated for heart failure patients with ischaemic and non-ischaemic MR. The survival distributions were compared using the log-rank test. To explore the association of variables with the occurrence of vasoplegia, univariable logistic regression analysis was performed. Odds ratios (OR) with 95% confidence intervals (CI) were reported. For each variable with a p-value <0.100 during univariable analysis, a multivariable logistic regression analysis was performed to assess their independent association with vasoplegia after adjusting for age, sex, and ischaemic heart failure. Results Study Population A total of 127 patients with LVEF ≤ 35% and moderate to severe functional MR underwent RMA (as a single procedure or with concomitant tricuspid valve annuloplasty, CSD implantation, or coronary artery bypass grafting) at the authors’ institution between 2006 and 2015. Because 5 patients in whom the presence of vasoplegia could not be assessed owing to absence of cardiac index measurements were excluded, the final population consisted of 122 patients. The baseline characteristics are described in Table 1. Mean age was 65 ± 9 years and the majority of patients were male (66%). Mean LVEF was 27 ± 6%. Concomitant procedures were tricuspid valve annuloplasty (66%), CSD implantation (43%) and coronary artery bypass grafting (51%). In total, 64 patients (52%) had functional MR owing to non-ischaemic heart failure and 58 patients (48%) because of ischaemic heart failure. As expected, baseline characteristics were different between these patient groups (Table 1). Patients with non-ischaemic MR were on average 7 years younger (p <0.001), had a 5% lower mean LVEF (p <0.001), and had more often NYHA class III and IV symptoms (73% vs. 50%, p = 0.009). In addition, patients with non- ischaemic MR had less often a history of previous cardiac surgery and more often used mineralocorticoid receptor antagonists and diuretics. Furthermore, patients with non- ischaemic MR more often received concomitant tricuspid valve annuloplasty and CSD implantation. Coronary artery bypass grafting was performed in 91% of patients with ischaemic MR. Fourteen percent of patients with non-ischaemic MR received concomitant coronary artery bypass grafting for single vessel coronary artery disease. Because coronary artery disease could not account for the degree of LV dysfunction on echocardiography in these patients, aetiology of MR was classified as non-ischaemic. A longer mean procedure time was observed in ischaemic compared with non-ischaemic MR patients (median 336 minutes [IQR 293 – 407] vs. 267 minutes [IQR 235 – 314], p <0.001). The same was seen for cross-clamp time (median 127 minutes [IQR 110 – 164] vs. 80 [IQR 63 – 100], p <0.001) and CPB time (median 186 minutes [IQR 154 – 227] v 135 [IQR 118 – 167], p <0.001). Table 1. Characteristics of the study population (n = 122). Overall Non-ischaemic MR ▇▇▇▇▇▇▇▇▇ MR p-value¥ n = 122 n = 64 n = 58 Age (years) 65 ± 9 62 ± 9 69 ± 9 <0.001 Male sex 66% 61% 72% 0.249 Body mass index 26 ± 4 26 ± 3 27 ± 4 0.093 (kg/m2) Diabetes 28% 27% 29% 0.840 Prior CVA or TIA 10% 11% 9% 0.766 Prior hypertension 38% 30% 47% 0.063 LVEF (%) 27 ± 6 25 ± 5 30 ± 5 <0.001 NYHA class III or IV 62% 73% 50% 0.009 Pulmonary 57% 64% 50% 0.144 hypertension Previous cardiac surgery 7% 2% 12% 0.027 EuroSCORE II (%) 9(5-13) 9 (6-13) 8 (5-15) 0.693 Preoperative laboratory assessment Anemia 23% 19% 28% 0.285 Creatinine clearance 62(49-80) 62 (54-83) 60 (44-78) 0.222 (ml/min) Medication Beta-blocker 80% 78% 81% 0.823 ACE inhibitor/ARB 83% 86% 79% 0.349 MRA 56% 67% 43% 0.010 Diuretics 91% 98% 83% 0.003 Inotropes 4% 6% 2% 0.368 Concomitant procedures TVP 66% 81% 48% <0.001 CSD 43% 81% 0% <0.001 CABG 51% 14% 91% <0.001 Cross clamp time (min)* 104(74-133) 80 (63-100) 127 (110-164) <0.001 CPB time (min) 155(131-205) 135 (118-167) 186 (154-227) <0.001 Procedure time (min) 296(255-360) 267 (235-314) 336 (293-407) <0.001 ICU time (days) 3 (1-5) 3 (2-6) 3 (1-5) 0.654 * Data based on 120 patients. ¥ comparison of patients with ischaemic vs non-ischaemic MR. Continuous data are presented as mean±SD or median(IQR). Categorical data are presented as numbers (%). ACE = Angiotensin- converting enzyme, ARB = angiotensin receptor blocker, CABG = coronary artery bypass grafting, CPB = cardiopulmonary bypass, CSD = cardiac support device, CVA = cerebrovascular accident, ICU = intensive care unit, IQR = interquartile range, LVEF = left ventricular ejection fraction, MR = mitral regurgitation, MRA = mineralocorticoid receptor antagonist, NYHA = New York Heart Association, TIA = transient ischaemic attack, TVP = tricuspid valvuloplasty. Incidence and clinical impact of vasoplegia The incidence of vasoplegia in heart failure patients with functional MR was 19% (Figure 1). The incidence of vasoplegia was not significantly different between ischaemic and non-ischaemic MR patients (16% vs. 22%, p = 0.488). As shown in Figure 2, the duration of intensive care unit (ICU) admission was longer in patients with vasoplegia (median 8 days [IQR 5 – 26]) compared with patients without vasoplegia (2 days [IQR 1 – 4], p <0.001). In addition, renal failure occurred more often in patients with vasoplegia (48% vs. 8%, p <0.001). Accordingly, patients with vasoplegia received more continuous ▇▇▇▇-venous hemofiltration (44% vs. 4%, p <0.001). Furthermore, both 30-day (78% vs. 98%, p <0.001) and 90-day survival rates (65% vs. 93%, p <0.001) were lower in patients with vasoplegia compared with patients without vasoplegia (Figure 3, A). The same applies when the population is stratified for ischaemic (56% vs. 90%, p = 0.002) and non-ischaemic MR patients (71% vs. 96%, p = 0.004; Figure 3, B). There was no significant difference in survival when vasoplegic patients with ischaemic MR were compared with vasoplegic patients with non-ischaemic MR (p = 0.458). The same applies to non- vasoplegic patients (p = 0.234).