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Exercise hemodynamic improvement after aorta-coronary artery bypass surgery
ABSTRACTS
EXERCISE TESTING IN THE FOLLOW UP OF PERIOPERATIVE MYOCARDIAL INFARCTION Robert D. Wiens, M.D., FACC, John E. Codd, M.D., George C. Kaiser, M.D., FACC, Hendrick B. Barrier,M.D., FACC, Vallee L. Willman, M.D., and Hiltrud Mueller, M.D., FACC, St. Louis University School of Medicine, St. Louis, Missouri. The development of a perioperative myocardial infarction during coronary.artery bypass surgery is a known complication but its effect on long term mortality and morbidity is not currently understood. To evaluate this problem, we have defined a population of 100 patients, 50 with perioperative infarction and 50 without ECG changes noted postoperatively. They were matched by age, number of vessels grafted, presence of infarction prior to surgery, postoperative graft patency and level of ventricular function. Follow up exercise tests are available in 50 patients, with 20 in the perioperative infarction group. The mean follow up for the whole group was 26.2 months. Results of exercise revealed no difference in the incidence of a positive test for ischemia. presence of arrhythmias or the intraexercise development of hypotension. Although the length of exercise in the noninfarct group was 718 + 231 seconds and the infarct group achieved a mean revel of 576 + 255 seconds, the difference does not have a P value of less than 0.05. The study demonstrates no difference between the two groups and implies no major long term functional consequence in the group with a perioperative myocardial infarction.
EXERCISE HEMODYNAMIC IMPROVEMENT AFTER AORTA-CORONARY ARTERY BYPASS SURGERY Ronald E. Vlietstra, MD; James H. Chesebro, MD, FACC; Robert L. Frye, MD, FACC; Robert B. Wallace, MD, Mayo Clinic and Mayo Foundation, Rochester, Minn. The hemodynamic response to 3 min of 150 kg-m/min supine bicycle exercise (HRE) was measured both before and 3-36 mo (mean 17) after aorta-coronary artery bypass surgery In 39 patients (pts) with significant coronary artery (CA) disease (stenoses >75%). HRE was considered to be abnormal if supine resting left ventricular end-diastolic pressure (LVEDP) was >I6 mm Hg, with feet up was >19 mm Hg, or exercise increase in LVEDP was >5 mm Hg. In 32 pts the preoperative (preop) HRE was abnormal; postoperatively (postop) 11 of these 32 became normal (Gp N), whereas 21 remained abnormal (Gp A). Mean (? SD) LVEDPs (mm Hg) were: Postop Preop Gp N Gp A P Gp N Gp A P Suuine rest 15 + 5 16 + 4 >0.5 12 ? 3 17 f 5 CO.01 Feet up 18 + 3 18 + 5 >0.5 14 + 3 19 + 5 co.01 Exercise 32 + 5 31 + 7 >0.5 16 i: 5 28 t 7
410
February 1978
The American Journal of CARDIOLOGY
EFFECT OF HYPOTHERMIA AND CARDIOPULMONARY PHARMACOKINETICS OF PROPRANOLOL
BYPASS ON THE
Russell G. McAllister, Jr., MD, FACC; David W. Bourne, PhD; Lewis W. Dittert, PhD; Edward P. Todd, MD. VA Hospital and the University of Kentucky Medical Center, Lexington, Kentucky Propranolol (P) may be useful during cardiac surgery (CS), since pretreatment with this drug prevents the hypokalemia resulting from hypothermia (H) and cardioSerial plasma concentrations pulmonary bypass (CPB). (PC's) of P were measured during CS in 10 patients who had been treated chronically with P. Although no further P was given during CS, P levels (corrected for plasma volume dilution) were significantly higher after only 10 minutes of H+CPB than in the preoperative period (42.5 + 4.5 vs 30.8 + 6.8 ng/ml; ~40.05). P PC's remained elevated throughout the CS, falling to or below prePrecise kinetic operative values only after rewarming. analysis of the data was difficult, however, due to the variables inherent in CS. To define the kinetic alterations due to H, intravenous P (1 mg/kg) was given twice to each of six mongrel dogs, first after anesthesia only, then after anesthesia plus cooling to 2pC in a water bath. Serial P PC's were measured in each experiment and the elimination kinetics calculated. Compared with the paired normothermic control studies, H caused a decrease in P half-life (T/2: 73.6 + 15.2 to 45.0 + 10.2 min; p(O.01) and a marked contraction in the volume of distribution (Vd: 6.78 + 1.65 to 2.08 + 0.58 L/kg; p 4 0.001). The total body clearance of P decreased by half during H. These data suggest that H alone significantly alters the pharmacokinetics of P, both by decreasing the Vd and by slowing the rate of metabolic elimination of the drug. Therefore, small doses of P given prior to H+CPB may produce higher plasma drug levels (and thus effects) than anticipated.
EXTRACRANIAL CAROTID OCCLUSIVE DISEASE AS A RISK FACTOR IN CARDIOVASCULAR SURGERY Mark M. Kartchner, MD, FACS; Lorin P. McRae, Ph.D. Tucson Medical Center, Tucson, Arizona The coexistence of extracranial carotid occlusive disease increases the risk encounteredinperforming major cardiovascular surgery, especially if systemic hypotension may occur during or after surgery. Reduction of internal carotid blood flow secondary to extracranial carotid occlusive disease is reliably determined pre-operatively by oculoplethysmography (OPG), the noninvasive comparative timing of simultaneously recorded ocular pulse waveforms. OPG studies were performed on patients being evaluated for 216 cardiovascular procedures consisting of 78 cardio-thoracic, 64 aortic, and 74 peripheral arterial operations. Negative OPG studies were obtained in 144 cases with subsequent non-carotid surgery resulting in two strokes due to emboli. Of the 72 positive OPG evaluations, 35 first underwent carotid endarterectomy and then the other cardiovascular surgery without neurologic sequelae. One patient with positive OPG studies evolved a frank stroke the day before his scheduled aortic aneurism surgery. Of the other 36 patients with positive OPG studies who had non-carotid cardiovascular operations, seven (19%) incurred surgery related strokes. The safety and reliability of OPG makes its use desirable prior to any angiography in anticipation of cardiovascular surgery to determine those patients for whom concurrent carotid arteriography should be performed. If clinically feasible, priority should be given to carotid endarterectomy before undertaking other cardiovascular procedures when significant internal carotid blood flow reduction indicative of extracranial carotid occlusive disease is detected by oculoplethysmography.
Volume 41
EXERCISE TESTING IN THE FOLLOW UP OF PERIOPERATIVE MYOCARDIAL INFARCTION Robert D. Wiens, M.D., FACC, John E. Codd, M.D., George C. Kaiser, M.D., FACC, Hendrick B. Barrier,M.D., FACC, Vallee L. Willman, M.D., and Hiltrud Mueller, M.D., FACC, St. Louis University School of Medicine, St. Louis, Missouri. The development of a perioperative myocardial infarction during coronary.artery bypass surgery is a known complication but its effect on long term mortality and morbidity is not currently understood. To evaluate this problem, we have defined a population of 100 patients, 50 with perioperative infarction and 50 without ECG changes noted postoperatively. They were matched by age, number of vessels grafted, presence of infarction prior to surgery, postoperative graft patency and level of ventricular function. Follow up exercise tests are available in 50 patients, with 20 in the perioperative infarction group. The mean follow up for the whole group was 26.2 months. Results of exercise revealed no difference in the incidence of a positive test for ischemia. presence of arrhythmias or the intraexercise development of hypotension. Although the length of exercise in the noninfarct group was 718 + 231 seconds and the infarct group achieved a mean revel of 576 + 255 seconds, the difference does not have a P value of less than 0.05. The study demonstrates no difference between the two groups and implies no major long term functional consequence in the group with a perioperative myocardial infarction.
EXERCISE HEMODYNAMIC IMPROVEMENT AFTER AORTA-CORONARY ARTERY BYPASS SURGERY Ronald E. Vlietstra, MD; James H. Chesebro, MD, FACC; Robert L. Frye, MD, FACC; Robert B. Wallace, MD, Mayo Clinic and Mayo Foundation, Rochester, Minn. The hemodynamic response to 3 min of 150 kg-m/min supine bicycle exercise (HRE) was measured both before and 3-36 mo (mean 17) after aorta-coronary artery bypass surgery In 39 patients (pts) with significant coronary artery (CA) disease (stenoses >75%). HRE was considered to be abnormal if supine resting left ventricular end-diastolic pressure (LVEDP) was >I6 mm Hg, with feet up was >19 mm Hg, or exercise increase in LVEDP was >5 mm Hg. In 32 pts the preoperative (preop) HRE was abnormal; postoperatively (postop) 11 of these 32 became normal (Gp N), whereas 21 remained abnormal (Gp A). Mean (? SD) LVEDPs (mm Hg) were: Postop Preop Gp N Gp A P Gp N Gp A P Suuine rest 15 + 5 16 + 4 >0.5 12 ? 3 17 f 5 CO.01 Feet up 18 + 3 18 + 5 >0.5 14 + 3 19 + 5 co.01 Exercise 32 + 5 31 + 7 >0.5 16 i: 5 28 t 7
410
February 1978
The American Journal of CARDIOLOGY
EFFECT OF HYPOTHERMIA AND CARDIOPULMONARY PHARMACOKINETICS OF PROPRANOLOL
BYPASS ON THE
Russell G. McAllister, Jr., MD, FACC; David W. Bourne, PhD; Lewis W. Dittert, PhD; Edward P. Todd, MD. VA Hospital and the University of Kentucky Medical Center, Lexington, Kentucky Propranolol (P) may be useful during cardiac surgery (CS), since pretreatment with this drug prevents the hypokalemia resulting from hypothermia (H) and cardioSerial plasma concentrations pulmonary bypass (CPB). (PC's) of P were measured during CS in 10 patients who had been treated chronically with P. Although no further P was given during CS, P levels (corrected for plasma volume dilution) were significantly higher after only 10 minutes of H+CPB than in the preoperative period (42.5 + 4.5 vs 30.8 + 6.8 ng/ml; ~40.05). P PC's remained elevated throughout the CS, falling to or below prePrecise kinetic operative values only after rewarming. analysis of the data was difficult, however, due to the variables inherent in CS. To define the kinetic alterations due to H, intravenous P (1 mg/kg) was given twice to each of six mongrel dogs, first after anesthesia only, then after anesthesia plus cooling to 2pC in a water bath. Serial P PC's were measured in each experiment and the elimination kinetics calculated. Compared with the paired normothermic control studies, H caused a decrease in P half-life (T/2: 73.6 + 15.2 to 45.0 + 10.2 min; p(O.01) and a marked contraction in the volume of distribution (Vd: 6.78 + 1.65 to 2.08 + 0.58 L/kg; p 4 0.001). The total body clearance of P decreased by half during H. These data suggest that H alone significantly alters the pharmacokinetics of P, both by decreasing the Vd and by slowing the rate of metabolic elimination of the drug. Therefore, small doses of P given prior to H+CPB may produce higher plasma drug levels (and thus effects) than anticipated.
EXTRACRANIAL CAROTID OCCLUSIVE DISEASE AS A RISK FACTOR IN CARDIOVASCULAR SURGERY Mark M. Kartchner, MD, FACS; Lorin P. McRae, Ph.D. Tucson Medical Center, Tucson, Arizona The coexistence of extracranial carotid occlusive disease increases the risk encounteredinperforming major cardiovascular surgery, especially if systemic hypotension may occur during or after surgery. Reduction of internal carotid blood flow secondary to extracranial carotid occlusive disease is reliably determined pre-operatively by oculoplethysmography (OPG), the noninvasive comparative timing of simultaneously recorded ocular pulse waveforms. OPG studies were performed on patients being evaluated for 216 cardiovascular procedures consisting of 78 cardio-thoracic, 64 aortic, and 74 peripheral arterial operations. Negative OPG studies were obtained in 144 cases with subsequent non-carotid surgery resulting in two strokes due to emboli. Of the 72 positive OPG evaluations, 35 first underwent carotid endarterectomy and then the other cardiovascular surgery without neurologic sequelae. One patient with positive OPG studies evolved a frank stroke the day before his scheduled aortic aneurism surgery. Of the other 36 patients with positive OPG studies who had non-carotid cardiovascular operations, seven (19%) incurred surgery related strokes. The safety and reliability of OPG makes its use desirable prior to any angiography in anticipation of cardiovascular surgery to determine those patients for whom concurrent carotid arteriography should be performed. If clinically feasible, priority should be given to carotid endarterectomy before undertaking other cardiovascular procedures when significant internal carotid blood flow reduction indicative of extracranial carotid occlusive disease is detected by oculoplethysmography.
Volume 41