Methods

Consecutive patients aged >18 years, who underwent nonemergent, major, noncardiothoracic, and nonvascular surgery from January 2010 to January 2012, at Haydarpaşa Numune Education and Research Hospital were eligible for enrollment. A total of 1,200 patients with native valves (control group) and 140 patients with MHVs (77 aortic, 46 mitral, and 17 double valve) were prospectively followed up for a minimum of 3 months after surgery. All patients provided informed consent, and the institutional review board approved the study. The collection of patient data included patient age, gender, body mass index, preoperative medications, American Society of Anesthesiologists physical status, and co-morbidities. We used the Revised Cardiac Risk Index score for each patient, assigning 1 point for each of the following risk factors: high-risk surgery type (defined as intraperitoneal, intrathoracic, or suprainguinal vascular procedures), ischemic heart disease, congestive heart failure, history of cerebrovascular disease, insulin therapy for diabetes, and preoperative serum creatinine >2.0 mg/dl. Anesthetic management, monitoring, and other aspects of perioperative management were at the discretion of the attending physician. Electrocardiography and cardiac biomarkers (creatine kinase-MB and troponin I) were evaluated 1 day before surgery, immediately after surgery, and on postoperative days 1, 3, and 7. Standard transthoracic echocardiography was performed in all patients using Vivid Three System (Vivid 3 pro, GE Vingmed, Milwaukee, Wisconsin) before surgery.

Patients presenting for surgery requiring only local anesthesia or monitored anesthesia care and outpatient surgical procedures were excluded. The patients were also excluded for any of the following reasons: (1) written informed consent not obtained; (2) emergent surgery; (3) patients with an American Society of Anesthesiologists classification of 5 (not expected to live 24 hours, irrespective of surgery); (4) history of heparin-induced thrombocytopenia; (5) weight >100 kg; (6) chronic liver disease or severe chronic renal insufficiency (i.e., creatinine clearance <20 ml/min); and (7) patients with a bioprosthetic heart valve. Vascular and intrathoracic surgery was not performed at our institution. In our study patients, major gastrointestinal surgery (laparotomy, advanced bowel surgery, gastric surgery), major gynecologic cancer surgery (abdominal hysterectomy and oophorectomy for cancer), major open or transurethral urologic surgery (cystectomy, radical nephrectomy, total prostatectomy), head and neck surgery, and hip or knee arthroplasty were included. The cardiac risk assessment, preoperative preparation, drug therapy, and postoperative follow-up were completed according to the current American College of Cardiology/American Heart Association guidelines. Infective endocarditis prophylaxis was performed according to the current guidelines in patients with MHVs. Periprocedural anticoagulation was performed according to the American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Warfarin was withheld for 5 days before surgery. The first dose of enoxaparin was started 24 to 36 hours after the last dose of warfarin and then stopped 24 hours before surgery. A preprocedure international normalized ratio was obtained the evening before the procedure. Surgery was performed if the international normalized ratio was <1.5. Enoxaparin 1 mg/kg, twice daily, was restarted 24 hours after the procedure, and warfarin was resumed 12 to 24 hours after the procedure, with the patient’s usual daily dose.

Treatment with enoxaparin was maintained until warfarin was considered effective, when ≥2 international normalized ratio laboratory determinations were within the therapeutic range, according to the published recommendations. There were occasional variations in the perioperative anticoagulation management strategies, including the start and/or stop time of warfarin and enoxaparin according to the anticipated thromboembolic and bleeding risks. The study outcomes were cardiac complications, arterial thromboembolism, noncardiac complications, bleeding, and death within 3 months after surgery.

The perioperative cardiovascular complications were defined as the occurrence of severe arrhythmias requiring treatment, acute heart failure, acute coronary syndrome (nonfatal acute myocardial infarction or unstable angina), pulmonary embolism, and nonfatal cardiac arrest. Perioperative myocardial infarction was defined according to the universal definition of myocardial infarction.

Arterial thromboembolic events were defined as a cardiac valvular or mural thrombus confirmed by transthoracic or transesophageal echocardiography, stroke, transient ischemic attack, or any symptomatic systemic embolism. Acute ischemic stroke was defined as rapidly developing clinical signs of focal disturbance of cerebral function, lasting >24 hours or leading to death with no apparent cause other than that of a vascular origin. A focal disturbance lasting <24 hours was classified as a transient ischemic attack. Intracranial events were confirmed by computed tomography or magnetic resonance imaging. Peripheral arterial thromboembolism was confirmed by arteriography, magnetic resonance angiography, spiral computed tomography, or Doppler studies. All patients with MHVs who experienced arterial thromboembolic events had undergone transesophageal echocardiography.

Noncardiovascular complications included lobar pneumonia confirmed by chest radiography and requiring antibiotic therapy, acute renal failure requiring dialysis, respiratory failure requiring intubation for >2 days or reintubation, wound infection, and bacteremia. Major bleeding was defined as fatal or life-threatening, at a critical location (retroperitoneal, intracranial, intraocular, or intraspinal), the necessity for acute medical diagnostic procedures or medical intervention or repeat surgery, or administration of ≥2 U of packed red blood cells. Minor bleeding was defined as all other reported bleeding events not meeting the criteria for a major bleeding event that did not require hospital admission or transfusion.

The data were analyzed using SPSS for Windows, version 15 (SPSS, Chicago, Illinois). The continuous variables are expressed as the mean ± standard deviation and were compared between groups using the 2-tailed Student t test. Nonparametric tests were also used when necessary (Mann-Whitney U test). The Fisher exact (chi-square) test was used to compare the categorical variables. For all analyses, p <0.05 was considered statistically significant.

Results

The clinical characteristics and preoperative laboratory variables for patients with native and mechanical valves are listed in Table 1 . Atrial fibrillation was more prevalent in patients with MHVs than in those with native valves (31.4% vs 13.5%, respectively; p <0.001). No significant differences were seen regarding the type of surgical procedure, New York Heart Association functional capacity, American Society of Anesthesiologists status, and Revised Cardiac Risk Index between patients with mechanical and native valves. The preoperative left ventricular ejection fraction was similar in patients with native and MHVs (58.52 ± 8.75 vs 58.64 ± 8.89, respectively; p = 0.439). The mean platelet volume was significantly greater (9.13 ± 8.07 vs 8.80 ± 5.56 fL, respectively; p = 0.039), and the hemoglobin concentration was significantly lower (12.02 ± 1.50 vs 12.38 ± 1.86 g/dl, respectively; p <0.001) in patients with MHVs than in those without MHVs.

The perioperative adverse events are summarized in Table 2 . The incidence of perioperative adverse cardiovascular events, bleeding, thromboembolism, noncardiovascular events, and mortality were similar in patients with and without MHVs. Twenty-four patients (2%) with native valves (15 acute ischemic stroke, 6 transient ischemic attack, 2 lower extremity arterial embolism, and 1 intracardiac mural thrombosis) and 5 patients (3.6%) with MHVs experienced thromboembolic complications (2 acute ischemic stroke, 1 transient ischemic attack, and 1 amaurosis fugax) within 3 months after the procedure (p = 0.319). All 5 patients with MHVs and arterial thromboembolic events underwent transesophageal echocardiography, which revealed a nonobstructive prosthetic mitral valve thrombosis in 1 patient and left atrial appendix thrombosis in 1 patient. No difference was found in the postoperative adverse events or death in patients with aortic, mitral, or double MHVs ( Figure 1 ).

Table 2

Perioperative adverse events

Complications	Native Valves (n = 1,200)	MHV (n = 140)	Aortic MHV (n = 77)	Mitral MHV (n = 46)	Double MHV (n = 17)	p Value
Cardiovascular	130 (10.8%)	15 (10.7%)	8 (10.4%)	5 (10.9%)	2 (11.8%)	0.985
Acute coronary syndrome	40 (3.3%)	4 (2.8%)	2 (2.6%)	1 (2.2%)	1 (5.9%)	0.329
Acute heart failure	35 (2.9%)	5 (3.6%)	3 (3.9%)	1 (2.2%)	1 (5.9%)	0.423
Severe arrhythmia	26 (2.2%)	3 (2.1%)	2 (2.6%)	1 (2.2%)	0	0.356
Pulmonary embolism	19 (1.6%)	2 (1.4%)	1 (1.3%)	1 (2.2%)	0	0.856
Nonfatal cardiac arrest	10 (0.8%)	1 (0.7%)	0	1 (2.2%)	0	0.741
Noncardiovascular	143 (11.9%)	16 (11.4%)	9 (11.7%)	5 (10.9%)	2 (11.8%)	0.989
Wound infection	81 (6.7%)	8 (5.7%)	5 (6.5%)	2 (4.3%)	1 (5.9%)	0.943
Respiratory failure	14 (1.2%)	2 (1.4%)	1 (1.3%)	1 (2.2%)	0	0.542
Lobar pneumonia	21 (1.8%)	3 (2.1%)	1 (1.3%)	1 (2.2%)	1 (5.9%)	0.458
Acute renal failure	14 (1.2%)	2 (1.4%)	2 (2.6%)	0	0	0.346
Bacteremia	13 (1.1%)	1 (0.7%)	0	1 (2.2%)	0	0.658
Bleeding
Minor	128 (10.7%)	21 (15%)	11 (14.3%)	7 (15.2%)	3 (17.6%)	0.939
Major	42 (3.5%)	5 (3.6%)	3 (3.9%)	1 (2.2%)	1 (5.9%)	0.760
Thromboembolic events	24 (2%)	5 (3.6%)	2 (2.6%)	2 (4.3%)	1 (5.9%)	0.319
Mortality	16 (1.3%)	2 (1.4%)	1 (1.3%)	1 (2.2%)	0	0.804

Only gold members can continue reading. Log In or Register to continue

Share this:

• Click to share on Twitter (Opens in new window)
• Click to share on Facebook (Opens in new window)

Related

Related posts:

1. Early Readmissions After Percutaneous Coronary Intervention in a Rural Tertiary Care Center (from the Guthrie Health Off-Label Stent [GHOST] Registry)
2. Comparison of Coronary Calcium Screening Versus Broad Statin Therapy for Patients at Intermediate Cardiovascular Risk
3. Utility of Cardiac Magnetic Resonance Imaging to Differentiate Cardiac Sarcoidosis from Arrhythmogenic Right Ventricular Cardiomyopathy
4. Meta-Analysis of Cardiovascular Outcomes With Dronedarone in Patients With Atrial Fibrillation or Heart Failure

Stay updated, free articles. Join our Telegram channel

Join