Gilles Godet

Dipyridamole-Thallium Scintigraphy and Gated Radionuclide Angiography to Assess Cardiac Risk before Abdominal Aortic Surgery

BACKGROUND Because many patients with atherosclerotic disease of the abdominal aorta also have coronary artery disease, assessment of cardiac risk before abdominal aortic surgery has received much attention. Our prospective study was designed to identify predictors of cardiac risk in consecutive patients evaluated preoperatively with dipyridamole-thallium single-photon-emission computed tomography (SPECT) to assess myocardial perfusion and radionuclide angiography to measure left ventricular ejection fraction. METHODS Clinical and scintigraphic data were collected prospectively during hospitalization in 457 consecutive patients undergoing elective abdominal aortic surgery. Adverse cardiac outcomes were predicted with multivariate analyses. RESULTS Eighty-six patients (19 percent) had one or more of the following postoperative complications: prolonged myocardial ischemia (61 patients), myocardial infarction (22), congestive heart failure (20), and severe ventricular tachyarrhythmia (2). Twenty patients died postoperatively (4.4 percent), half of them from cardiac causes. Information about myocardial perfusion obtained from dipyridamole-thallium SPECT did not accurately predict adverse cardiac outcomes. The best correlates of cardiac complications were definite clinical evidence of coronary artery disease (odds ratio, 2.6; 95 percent confidence interval, 1.6 to 4.3) and age greater than 65 years (odds ratio, 2.3; 95 percent confidence interval, 1.4 to 3.6). Measurement of the ejection fraction was useful only in the prediction of left ventricular failure. Age greater than 65 years was the only predictor of death (odds ratio, 26.4; 95 percent confidence interval, 3.5 to 200.0). CONCLUSIONS The presence of definite clinical evidence of coronary artery disease and older age were the most important preoperative predictors of an adverse cardiac outcome after abdominal aortic surgery. These results suggest that the routine use of dipyridamole-thallium SPECT and radionuclide angiography for screening before abdominal aortic surgery may not be justified.

Early and Delayed Myocardial Infarction after Abdominal Aortic Surgery

Background: Although postoperative myocardial infarction (PMI) after vascular surgery has been described to be associated with prolonged ischemia, its exact pathophysiology remains unclear. Methods: The authors used intense cardiac troponin I (cTnI) surveillance after abdominal aortic surgery in 1,136 consecutive patients to better evaluate the incidence and timing of PMI (cTnI ≥ 1.5 ng/ml) or myocardial damage (abnormal cTnI < 1.5 ng/ml). Results: Abnormal cTnI concentrations was noted in 163 patients (14%), of which 106 (9%) had myocardial damage and 57 (5%) had PMI. In 34 patients (3%), PMI was preceded by a prolonged (> 24 h) period of increased cTnI (delayed PMI), and in 21 patients (2%), the increase in cTnI lasted less than 24 h (early PMI). The mean times from end of surgery to PMI were 37 ± 22 and 74 ± 39 h in the early PMI and delayed PMI groups, respectively (P < 0.001). The mean time between the first abnormal cTnI and PMI in the delayed PMI group was 54 ± 35 h, during which the cTnI profiles of the myocardial damage and delayed PMI groups were identical. In-hospital mortality rates were 24, 21, 7, and 3% for the early PMI, delayed PMI, myocardial damage, and normal groups, respectively. Conclusions: Intense postoperative cTnI surveillance revealed two types of PMI according to time of appearance and rate of increase in cTnI. The identification of early and delayed PMI may be suggestive of different pathophysiologic mechanisms. Abnormal but low postoperative cTnI is associated with increased mortality and may lead to delayed PMI.

Should the Angiotensin II Antagonists be Discontinued Before Surgery

Angiotensin II antagonists (AIIA) are part of a new rational treatment of hypertension. Because adverse circulatory effects during anesthesia can occur in patients chronically treated with angiotensin-converting enzyme inhibitors, some clinicians discontinue them at least 24 h before operation. No data are available concerning AIIA administration in patients scheduled for vascular surgery performed under general anesthesia. The aim of this prospective randomized study was to compare hemodynamics during induction of anesthesia in patients chronically treated with AIIA and those of patients not receiving this drug on the morning before operation. Thirty-seven patients chronically treated with AIIA for hypertension were randomly assigned to two groups: Group I: AIIA discontinued on the day before surgery (n = 18); Group II: AIIA given 1 h before anesthesia (n = 19). Patients received sufentanil 0.4 &mgr;g/kg, propofol 1.5 mg/kg, and atracurium 0.5 mg/kg. During the procedure, the anesthesiologist was required to maintain systolic blood pressure and heart rate within 30% of baseline values using intravascular fluid administration and vasoconstric- tors (e.g., ephedrine, phenylephrine, or terlipressin). Hemodynamic variables were recorded each 1 min. Hemodynamic study ended at incision. The number and duration of hemodynamic events were collected, and total doses of vasoactive drugs were noted in each group. Systolic arterial pressure was significantly decreased in Group II at 5, 15 and 23 min after induction of anesthesia (*P < 0.05). In this group, the decrease in systolic arterial pressure was associated with more frequent episodes of hypotension (AIIA withdrawn: 1 ± 1; AIIA given: 2 ± 1;P < 0.01), with a larger number of patients developing at least 1 episode of hypotension (AIIA withdrawn: 12; AIIA given: 19;P < 0.01), and a longer duration of an episode of hypotension (AIIA withdrawn: 3 ± 4 min; AIIA given: 8 ± 7 min;P < 0.01), and an increased need for vasoactive drugs. In conclusion, blockade of the renin-angiotensin system increases the potential hypotensive effect of anesthetic induction. A severe hypotensive episode, requiring vasoconstrictor treatment, occurs after induction of general anesthesia in patients chronically treated with AIIA. Recommendations to discontinue AIIA drugs on the day before the surgery may be justified. IMPLICATIONS This prospective randomized study demonstrated that more severe hypotensive episodes, requiring vasoconstrictor treatment, occur after induction of general anesthesia in patients chronically treated with AIIA and receiving this drug on the morning before operation, in comparison with those in whom AIIA were discontinued on the day before operation. Recommendations to discontinue these drugs on the day before the surgery may be justified.

The impact of postoperative discontinuation or continuation of chronic statin therapy on cardiac outcome after major vascular surgery.

BACKGROUND:Statins reduce cardiac morbidity in nonsurgical populations, and may benefit surgical patients. We sought to examine cardiac outcome in patients who continued, compared with those who discontinued, statin therapy after major vascular surgery. METHODS:Prospectively collected data were examined for an association between statin therapy and perioperative cardiac morbidity in patients undergoing infrarenal aortic surgery. Between January 2001 and December 2003, there were no guidelines for perioperative continuation of statins (discontinuation group, n = 491). From January 2004, guidelines were instituted whereby statin therapy was continued starting as soon as possible after surgery (continuation group, n = 178). The occurrence of cardiac myonecrosis (defined as an increase of cardiac troponin I more than the 99th percentile or 0.2 ng/mL) was analyzed. Intra-cohort (propensity score) and extra-cohort (Lee score) adjustments of the risk were performed. RESULTS:The median delay between surgery and resumption of statin therapy was 4 days and 1 day in the discontinuation and continuation groups (P < 0.001), respectively. Using propensity score matching for likelihood of preoperative treatment, the odds ratio associated with chronic statin treatment to predict myonecrosis for patients with versus without early postoperative statin resumption (continuation versus discontinuation groups) was 0.38 and 2.1 (relative risk reduction of 5.4; 95% confidence interval: 1.2-25.3, P < 0.001), respectively. The odds ratio after adjustment for the Lee score was 0.38 in the continuation group and 2.1 in the discontinuation group (relative reduction of 5.5; 95% confidence interval: 1.2-26.0, P < 0.001). Postoperative statin withdrawal (>4 days) was an independent predictor of postoperative myonecrosis (OR 2.9, 95% confidence interval 1.6-5.5). CONCLUSIONS:Discontinuation of statin therapy after major vascular surgery is associated with an increased postoperative cardiac risk, suggesting that statin therapy should be resumed early after major vascular surgery.

Prognostic value of troponin and creatine kinase muscle and brain isoenzyme measurement after noncardiac surgery: a systematic review and meta-analysis.

Background:There is uncertainty regarding the prognostic value of troponin and creatine kinase muscle and brain isoenzyme measurements after noncardiac surgery. Methods:The current study undertook a systematic review and meta-analysis. The study used six search strategies and included noncardiac surgery studies that provided data from a multivariable analysis assessing whether a postoperative troponin or creatine kinase muscle and brain isoenzyme measurement was an independent predictor of mortality or a major cardiovascular event. Independent investigators determined study eligibility and abstracted data in duplicate. Results:Fourteen studies, enrolling 3,318 patients and 459 deaths, demonstrated that an increased troponin measurement after surgery was an independent predictor of mortality (odds ratio [OR] 3.4, 95% confidence interval [CI] 2.2–5.2), but there was substantial heterogeneity (I2 = 56%). The independent prognostic capabilities of an increased troponin value after surgery in the 10 studies that assessed intermediate-term (≤ 12 months) mortality was an OR = 6.7 (95% CI 4.1–10.9, I2 = 0%) and in the 4 studies that assessed long-term (more than 12 months) mortality was an OR = 1.8 (95% CI 1.4–2.3, I2 = 0%; P < 0.001 for test of interaction). Four studies, including 1,165 patients and 202 deaths, demonstrated an independent association between an increased creatine kinase muscle and brain isoenzyme measurement after surgery and mortality (OR 2.5, 95% CI 1.5–4.0, I2 = 4%). Conclusions:An increased troponin measurement after surgery is an independent predictor of mortality, particularly within the first year; limited data suggest an increased creatine kinase muscle and brain isoenzyme measurement also predicts subsequent mortality. Monitoring troponin measurements after noncardiac surgery may allow physicians to better risk stratify and manage their patients.

Preoperative spinal cord arteriography in aneurysmal disease of the descending thoracic and thoracoabdominal aorta: preliminary results in 45 patients.

Between 1985 and 1988 45 patients with descending thoracic or thoracoabdominal aortic aneurysms underwent selective arteriography of the intercostal and lumbar arteries to delineate preoperatively the artery of Adamkiewicz and the thoracic radicular artery. Identification of these vessels failed in five patients (11%), was considered complete in 31 patients (69%) and incomplete in nine (20%). Selective arteriography classified these patients into four groups: groups A and B--the artery of Adamkiewicz arose respectively above and below the zone of operation; group C--the artery arose directly from the segment to be operated; and group D--origin could not be determined. All 30 patients in group C underwent a spinal cord revascularization procedure (complete in 20 cases, incomplete in 10). Spinal cord complications occurred in 9/45 patients (20%). No spinal cord complications occurred in groups A and B; their incidence was 5% in group C when revascularization was complete, and 50% when revascularization was incomplete; and 60% had complications in group D (p less than 0.01). Spinal cord complications were more frequent (p less than 0.05) when the artery of Adamkiewicz arose from an intercostal or lumbar artery obliterated at its aortic origin but filled through collaterals or when spinal cord circulation was interrupted for more than 45 minutes. This study confirms the importance of preserving arterial supply to the spinal cord during repair of descending thoracic and thoracoabdominal aneurysms. The information obtained from spinal cord arteriography allows the prediction of complications and informs the choice of the appropriate surgical technique.

Risk factors for Acute postoperative renal failure in thoracic or thoracoabdominal aortic surgery : A prospective study

Acute postoperative renal failure is a common complication of thoracic aorta, thoracoabdominal aorta, or aortic arch surgery.To identify variables associated with acute postoperative renal failure, we prospectively studied 475 consecutive patients undergoing thoracoabdominal aortic surgery over a 12-yr period, including those requiring emergent surgery. One hundred twenty-one (25%) patients developed acute postoperative renal failure, and 39 (8%) required hemodialysis. Using multivariate analysis, acute postoperative renal failure was significantly associated with the following variables: age >50 yr (odds ratio [OR] 2.90 [95% confidence interval 1.52-5.53]), preoperative serum creatinine >120 micro mol/L (OR 2.76 [1.70-4.48]), duration of left kidney ischemia >30 min (OR 2.01 [1.27-3.17]), packed red cells administration >5 units (OR 2.04 [1.24-3.37]), and Cell-Saver administration >5 units (OR 2.31 [1.34-1.96]). Reimplantation of visceral, renal arteries and the Adamkievicz artery; duration of visceral, spinal, and right kidney ischemia; requirement for fresh frozen plasma; administration of aprotinin; extracorporeal circulation; and procedures with circulatory arrest and profound hypothermia were not predictive of postoperative renal failure. In addition, age >50 yr (OR 5.59 [1.31-23.91]), requirement for packed red blood cells >5 unit (OR 3.91 [1.58-9.67]), and preoperative serum creatinine concentration >120 micro mol/L (OR 2.26 [1.13-4.53]) were independent factors for acute renal failure requiring hemodialysis. In conclusion, acute renal failure is often observed after thoracic aortic surgery. Numerous predictive factors must be considered when evaluating the etiology of this complication. Implications: Acute postoperative renal insufficiency is a common complication of thoracic aortic surgery. This study found that age >50 yr, preoperative renal dysfunction, duration of renal ischemia, and amount of blood transfusion are significant predictors of this complication. (Anesth Analg 1997;85:1227-32)

Target-controlled infusion for remifentanil in vascular patients improves hemodynamics and decreases remifentanil requirement

Remifentanil is a potent ultra-short-acting opioid, which permits rapid emergence. However, remifentanil is expensive and may have detrimental effects on hemodynamics in case of overdose. Target-controlled infusion (TCI) permits adapting infusion to pharmacokinetic models. In this prospective randomized study, we compared intra- and postoperative hemodynamics, remifentanil requirement during anesthesia, and postoperative morphine requirement in patients scheduled for carotid surgery, and receiving either continuous IV weight-adjusted infusion of remifentanil (RIVA) or TCI for remifentanil (TCIR). Forty-six patients were enrolled in this study: all were anesthetized by using TCI for propofol. Twenty-three received RIVA (0.5 &mgr;g · kg−1 · min−1) for the induction of anesthesia and endotracheal intubation, with the infusion rate decreased to 0.25 &mgr;g · kg−1 · min−1 after intubation, then adapted by step of 0.05 &mgr;g · kg−1 · min−1 according to hemodynamics. Twenty-three patients received TCIR (Minto model, Rugloop), with an effect-site concentration at 4 ng/mL during induction, then adapted by step of 1 ng/mL according to hemodynamics. All patients received atracurium and a 50% mixture of N2O/O2. Hemodynamic variables were recorded each minute. The number and duration of hemodynamic events were collected, and total doses of anesthetics (remifentanil and propofol) and vasoactive drugs were noted in both groups of patients. Data were analyzed by using unpaired t-tests. RIVA was significantly associated with more frequent episodes of intraoperative hypotension (16 versus 6, P < 0.001) and more frequent episodes of postoperative hypertension and/or tachycardia requiring more frequent administration of &bgr;-adrenergic blockers (16 vs 10, P < 0.04) in comparison with TCIR. The need for morphine titration was not significantly different between groups. TCIR led to a significantly smaller requirement of remifentanil (700 ± 290 versus 1390 ± 555 &mgr;g, P < 0.001) without difference in propofol requirement. This prospective randomized study demonstrated that, during carotid endarterectomy, in comparison with patients receiving remifentanil using continuous RIVA, TCI results in less hypotensive episodes during the induction of anesthesia, in fewer episodes of tachycardia and/or hypertension and a smaller &bgr;-adrenergic blocker requirement during recovery, and a decrease in remifentanil requirement. Recommendations to prefer TCI for remifentanil administration during carotid endarterectomy may be justified.

Does Preoperative Coronary Angioplasty Improve Perioperative Cardiac Outcome

Background: Percutaneous coronary intervention (PCI) is performed in patients with coronary artery disease who are undergoing major noncardiac procedures to reduce perioperative cardiac morbidity and mortality. However, the impact of this approach on postoperative outcome remains controversial. Methods: The authors analyzed a cohort of 1,152 patients after abdominal aortic surgery in which 78 patients underwent PCI. A propensity score analysis was performed. Also, using a logistic regression model, the authors determined variables associated with a severe postoperative coronary event or a death in patients without PCI. Then, in patients with PCI, they compared the expected and observed outcome. Results: Five variables (age > 75 yr, blood transfusion > 3 units, repeated surgery, preoperative hemodialysis, and previous cardiac failure) independently predicted (with 94% correctly classified) a severe postoperative coronary event, and five variables (age > 75 yr, repeated surgery, previously abnormal ST segment/T waves, previous hypertension, and previous cardiac failure) independently predicted (with 97% correctly classified) postoperative death. In the PCI group, the observed percentages of patients with a severe postoperative coronary event (9.0% [95% confidence interval, 4.4–17.4]) or death (5.1% [95% confidence interval, 2.0–12.5]) were not significantly different from the expected percentages (8.2 and 6.9%, respectively). When all patients were pooled together, the odds ratios of PCI were not significant. The propensity score analysis provided a similar conclusion. Conclusion: PCI did not seem to limit significantly cardiac risk or death after aortic surgery.

Terlipressin versus norepinephrine to correct refractory arterial hypotension after general anesthesia in patients chronically treated with renin-angiotensin system inhibitors

Background Terlipressin, a precursor that is metabolized to lysine-vasopressin, has been proposed as a drug for treatment of intraoperative arterial hypotension refractory to ephedrine in patients who have received long-term treatment with renin-angiotensin system inhibitors. The authors compared the effectiveness of terlipressin and norepinephrine to correct hypotension in these patients. Methods Among 42 patients scheduled for elective carotid endarterectomy, 20 had arterial hypotension following general anesthesia that was refractory to ephedrine. These patients were the basis of the study. After randomization, they received either 1 mg intravenous terlipressin (n = 10) or norepinephrine infusion (n = 10). Beat-by-beat recordings of systolic arterial blood pressure and heart rate were stored on a computer. The intraoperative maximum and minimum values of blood pressure and heart rate, and the time spent with systolic arterial blood pressure below 90 mmHg and above 160 mmHg, were used as indices of hemodynamic stability. Data are expressed as median (95% confidence interval). Results Terlipressin and norepinephrine corrected arterial hypotension in all cases. However, time spent with systolic arterial blood pressure below 90 mmHg was less in the terlipressin group (0 s [0–120 s]vs. 510 s [120–1011 s];P < 0.001). Nonresponse to treatment (defined as three boluses of terlipressin or three changes in norepinephrine infusion) occurred in zero and eight cases (P < 0.05), respectively. Conclusions In patients who received long-term treatment with renin-angiotensin system inhibitors, intraoperative refractory arterial hypotension was corrected with both terlipressin and norepinephrine. However, terlipressin was more rapidly effective for maintaining normal systolic arterial blood pressure during general anesthesia.