[Physiopathologic introduction to anesthesia and resuscitation of the vascular patient]

Coronary artery disease (CAD), arterial hypertension, chronic bronchitis and diabetes mellitus are the most frequently encountered diseases complicating the clinical course of the vascular patient. Clinical signs of cardiac or pulmonary disease are often absent in patients with decreased functional capacity due to claudication. For instance, clinical evidence of coronary artery disease was found in 36% of patients scheduled for different vascular surgical procedures, whereas coronary angiography revealed significant stenoses in as many as 53-68%. Patients with chronic hypertensive disease, coronary artery disease and increased impedance to left ventricular ejection due to atherosclerosis frequently develop impairment of left ventricular (LV) function. Even without clinical or radiological evidence, approximately 20-35% of vascular patients have a LV ejection fraction below 50% indicating impaired systolic LV function. The incidence of diabetes mellitus in vascular surgical patients is around 18%. When requiring insulin treatment, diabetes is an independent risk factor for postoperative ischemic events and congestive heart failure. Those with autonomic neuropathy are often asymptomatic as regards coronary artery disease. Coronary artery disease is responsible for over 50% of the immediate, medium- and long-term mortality and morbidity. Unstable myocardial ischemia, acute myocardial infarction which is detected by troponin I and ischemic pulmonary edema are the most common immediate postoperative cardiac complications. A large number of recent studies, using long-term ECG recording techniques, have allowed more accurate estimation of the incidence and time course of perioperative myocardial ischemia in vascular surgical patients. The highest incidence of ischemia when compared to daily life activities has been noted during the first two days after surgery but has been reported to remain elevated even 3-5 days after surgery. Interestingly, the incidence of intraoperative ischemia is lower than that observed during daily life. Knowledge of the etiology of perioperative myocardial infarction is essential if one is to improve cardiac outcome after vascular surgery. Many studies have addressed this important field in patients undergoing vascular surgery. They have documented a relationship between perioperative myocardial ischemia and postoperative myocardial infarction. Although postoperative myocardial infarctions are in most cases limited to endocardium (non Q wave infarction) they significantly reduce life expectancy of the vascular surgical patients. The reduction of cardiac risk following general surgery should focus on methods by which the incidence of myocardial ischemia, particularly during the postoperative period, could be reduced. These methods include intensive intraoperative analgesia or preventive administration of cardiovascular treatment which limit postoperative stress: alpha-2 agonists or betablocking agents. There are, at present, no studies which convincingly confirm an overall decreased mortality if coronary bypass surgery is performed prior to peripheral vascular surgery. Although it has been demonstrated that the mortality of the peripheral procedure is reduced to approximately one half, the mortality of a coronary bypass procedure in vascular surgical patients is five to eight times that recorded in a coronary artery bypass population without peripheral vascular disease. It remains to be shown if the use of coronary angioplasty prior to peripheral vascular surgery can provide a more satisfactory overall outcome. Several non-invasive techniques have been suggested to improve the identification of high-risk patients undergoing vascular surgery. These tests include exercise ECG, ambulatory ECG, dipyridamolethallium scintigraphy and determination of left ventricular ejection fraction by gated radionuclide imaging. (ABSTRACT TRUNCATED)