The long-term impact of early cardiovascular therapy intensification for postoperative troponin elevation after major vascular surgery.

BACKGROUND: Acute cardiac events are a frequent cause of morbidity after vascular surgery. The impact of early evidence-based treatment for patients with an acute cardiac event after vascular surgery on long-term postoperative outcomes has not been extensively studied. We hypothesized that providing appropriate evidence-based treatment to patients with elevated postoperative cardiac troponin levels may limit long-term mortality. METHODS: We conducted a study of 667 consecutive major vascular surgery patients with an elevated postoperative troponin I level. We then determined which of these patients received medical therapy as per the 2007 American College of Cardiology/American Heart Association recommendations for the medical management of patients with chronic stable angina. All patients with troponin elevation were then matched with 2 control patients without postoperative troponin elevation. Matching was done using logistic regression and nearest-neighbor matching methods. The primary study end point was 12 months survival without a major cardiac event (i.e., death, myocardial infarction, coronary revascularization, or pulmonary edema requiring hospitalization). RESULTS: Therapy was intensified in 43 of 66 patients (65%) who suffered a troponin I elevation after surgery. Patients with a troponin I elevation not receiving intensified cardiovascular treatment had a hazard ratio (HR) of 1.77 (95% confidence interval (CI), 1.13-2.42; P = 0.004) for the primary study outcome as compared with the control group. In contrast, patients with a troponin I elevation who received intensified cardiovascular treatment had an HR of 0.63 (95% CI, 0.10-1.19; P = 0.45) for the primary outcome as compared with the control group. Patients with a troponin I elevation not receiving treatment intensification likely were at higher risk for a major cardiac event (HR, 2.80; 95% CI, 1.05-24.2; P = 0.04) compared with patients who did receive treatment intensification. CONCLUSIONS: The main finding of this study was that in patients with elevated troponin I levels after noncardiac surgery, long-term adverse cardiac outcomes may likely be improved by following evidence-based recommendations for the medical management of acute coronary syndromes.

Can changes in arterial pressure be used to detect changes in cardiac output during volume expansion in the perioperative period?

BACKGROUND: Cardiac output (CO) is rarely monitored during surgery, and arterial pressure remains the only hemodynamic parameter for assessing the effects of volume expansion (VE). However, whether VE-induced changes in arterial pressure accurately reflect changes in CO has not been demonstrated. The authors studied the ability of VE-induced changes in arterial pressure and in pulse pressure variation to detect changes in CO induced by VE in the perioperative period. METHODS: The authors studied 402 patients in four centers. Hemodynamic variables were recorded before and after VE. Response to VE was defined as more than 15% increase in CO. The ability of VE-induced changes in arterial pressure to detect changes in CO was assessed using a gray zone approach. RESULTS: VE increased CO of more than 15% in 205 patients (51%). Areas under the receiver operating characteristic curves for VE-induced changes in systolic, diastolic, means, and pulse pressure ranged between 0.64 and 0.70, and sensitivity and specificity ranged between 52 and 79%. For these four arterial pressure-derived parameters, large gray zones were found, and more than 60% of the patients lay within this inconclusive zone. A VE-induced decrease in pulse pressure variation of 3% or more allowed detecting a fluid-induced increase in CO of more than 15% with a sensitivity of 90% and a specificity of 77% and a gray zone between 2.2 and 4.7% decrease in pulse pressure variation including 14% of the patients. CONCLUSION: Only changes in pulse pressure variation accurately detect VE-induced changes in CO and have a potential clinical applicability.

Impact of perioperative bleeding on the protective effect of ß-blockers during infrarenal aortic reconstruction.

BACKGROUND: The use of ß-blockers during the perioperative period remains controversial. Although some studies have demonstrated their protective effects regarding postoperative cardiac complications, others have demonstrated increased mortality when ß-blockers were introduced before surgery. METHODS: In this observational study involving 1,801 patients undergoing aortic reconstruction, we prospectively assessed ß-blocker therapy compared with no ß-blocker therapy, with regard to cardiac and noncardiac postoperative outcomes using a propensity score approach. The impact of ß-blockers was analyzed according to the intraoperative bleeding estimated by transfusion requirements. RESULTS: In-hospital mortality was 2.5% (n=45), ß-blocker use was associated with a reduced frequency of postoperative myocardial infarction (OR=0.46, 95% CI [0.26; 0.80]) and myocardial necrosis (OR=0.62, 95% CI [0.43; 0.88]) in all patients, but also with an increased frequency of multiple organ dysfunction syndromes (OR=2.78, 95% CI [1.71; 4.61]). In patients with severe bleeding (n=163; 9.1%), the frequency of in-hospital death (OR=6.65, 95% CI [1.09; 129]) and/or multiple organ dysfunction syndromes (OR=4.18, 95% CI [1.81; 10.38]) were markedly increased. Furthermore, no more than 28% of the patients who died presented with postoperative myocardial infarction, whereas 69% of the patient with a postoperative myocardial infarction also presented an excessive bleeding. CONCLUSIONS: Perioperative ß-blocker therapy was associated with an overall reduction in postoperative cardiac events. In the vast majority of patients with low perioperative bleeding, the global effect of ß-blockers was protective; in contrast, patients given ß-blockers who experienced severe bleeding had higher mortality and an increased frequency of multiorgan dysfunction syndrome.

Assessing the diagnostic accuracy of pulse pressure variations for the prediction of fluid responsiveness: a "gray zone" approach.

BACKGROUND: Respiratory arterial pulse pressure variations (PPV) are the best predictors of fluid responsiveness in mechanically ventilated patients during general anesthesia. However, previous studies were performed in a small number of patients and determined a single cutoff point to make clinical discrimination. The authors sought to test the predictive value of PPV in a large, multicenter study and to express it using a gray zone approach. METHODS: The authors studied 413 patients during general anesthesia and mechanical ventilation in four centers. PPV, central venous pressure, and cardiac output were recorded before and after volume expansion (VE). Response to VE was defined as more than 15% increase in cardiac output after VE. The following approaches were used to determine the gray zones: resampled and two-graph receiver operator characteristic curves. The impact of changes in the benefit-risk balance of VE on the gray zone was also evaluated. RESULTS: The authors observed 209 responders (51%) and 204 nonresponders (49%) to VE. The area under receiver operating characteristic curve was 0.89 (95% CI: 0.86-0.92) for PPV, compared with 0.57 (95% CI: 0.54-0.59) for central venous pressure (P < 10). The gray zone approach identified a range of PPV values (between 9% and 13%) for which fluid responsiveness could not be predicted reliably. These PPV values were seen in 98 (24%) patients. Changes in the cost ratio of VE moderately affected the gray zone limits. CONCLUSION: Despite a strong predictive value, PPV may be inconclusive (between 9% and 13%) in approximately 25% of patients during general anesthesia.

Impact of preoperative statin therapy on adverse postoperative outcomes in patients undergoing vascular surgery.

BACKGROUND: Chronic statin therapy is associated with reduced postoperative mortality. Renal and cardiovascular benefits have been described, but the effect of chronic statin therapy on postoperative adverse events has not yet been explored. METHODS: In this observational study involving 1,674 patients undergoing aortic reconstruction, we prospectively assessed chronic statin therapy compared with no statin therapy, with regard to serious outcomes, by propensity score and multivariable methods. RESULTS: In propensity-adjusted multivariable logistic regression (c-index: 0.83), statins were associated with an almost threefold reduction in the risk of death in patients undergoing major vascular surgery (odds ratio: 0.40; 95% CI: 0.28-0.59) and an almost twofold reduction in the risk of postoperative myocardial infarction (odds ratio: 0.52; 95% CI: 0.38-0.71). Likewise, the use of chronic statin therapy was associated with a reduced risk of postoperative stroke and renal failure. Statins did not significantly reduce the risk of pneumonia, multiple organ dysfunction syndrome, and surgical complications; however, in the case of postoperative multiple organ dysfunction syndrome (odds ratio: 0.34; 95% CI: 0.12-0.94) and surgical complications (odds ratio: 0.39; 95% CI: 0.17-0.86), reduced mortality was observed. CONCLUSIONS: Chronic statin therapy was associated with a reduction in all cardiac and vascular outcomes after major vascular surgery. Furthermore, in major adverse events, such as multiple organ dysfunction syndrome and surgical complications, statins were also associated with decreased mortality.

Type IV thoracoabdominal aneurysm repair: predictors of postoperative mortality, spinal cord injury, and acute intestinal ischemia.

Our purpose was to identify preoperative and intraoperative predictors of early mortality, spinal cord injury, or acute intestinal ischemia after repair of type IV thoracoabdominal aneurysm (TAA IV) as a basis for optimizing surgical indications and techniques. From January 1991 to June 2006 we operated on 171 patients for TAA IV. There were 149 men (87.1%) and 22 women (12.9%), with a mean age of 65.0 +/- 10.9 years (range 23-82). The underlying etiology was degenerative aneurysmal disease in 143 patients (83.6%). Twenty-two patients (12.8%) underwent emergent operation. Comorbidity included coronary disease in 72 patients (45.6%) including 39 who had undergone a revascularization procedure, arterial hypertension in 121 (70.1%), chronic obstructive pulmonary disease in 81 (47.4%), and chronic kidney insufficiency in 58 (33.9%). Seventy-six patients (44.4%) presented concurrent lesions involving at least one visceral artery. Spinal cord arteriography was performed in 91 patients (53.2%). In 25 cases (27.5%) arteriographic findings demonstrated the need for revascularization of the Adamkiewicz artery due to location of the ostium at or below the T12 level. Repair was carried out with cross-clamping only in 160 cases (93.6%). Partial cardiopulmonary bypass was used in 11 patients (6.4%). A total of 23 patients (13.4%) died postoperatively. The cause of death was acute intestinal ischemia in nine cases, multiple organ failure in seven, coagulation disorder in three, cardiac complications in two, and stroke in two. Spinal cord injury occurred in eight patients (4.7%) including two who died. According to univariate analysis, the significant predictors of early death were age over 70 years, degenerative aneurysmal disease, coronary artery disease, chronic renal insufficiency or visceral artery lesions, operator, duration of intestinal ischemia and use of a "complex" surgical technique. Although the only significant predictor of spinal cord injury was duration of digestive ischemia, an almost significant trend (p < 0.1) was observed for coronary artery disease, coronary bypass, and renal insufficiency. The significant predictors of acute intestinal ischemia were kidney insufficiency and visceral artery lesions, but coronary artery disease and previous coronary bypass were almost significant (p = 0.06). Frequent association of TAA IV with arteriosclerotic disease in elderly patients presenting coronary artery disease and chronic kidney insufficiency partly explains why early postoperative mortality remains high. The incidence of spinal cord injury suggests that preoperative spinal cord arteriography is mandatory for prevention. The frequency of intestinal ischemia is more problematic, but a better understanding of the underlying mechanism should enable development of preventive strategies.

Cerebrospinal fluid drainage and thoracic endovascular aneurysm repair.

Spinal cord complications including paraplegia and partial neurologic deficits remain a frequent problem during repair of descending thoracic or thoracoabdominal aortic aneurysms. Effective prevention of this dreaded complication is of paramount importance. Among the many adjuncts that have been proposed to prevent spinal cord complications, spinal fluid drainage is one that has been used by numerous teams. The aim of this review is to answer the following question: does spinal fluid drainage afford spinal cord protection during both open and endovascular repair of thoracic or thoracoabdominal aortic aneurysms?

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.

Echocardiographic Doppler assessment of pulmonary capillary wedge pressure in surgical patients with postoperative circulatory shock and acute lung injury.

BACKGROUND: In cardiac patients, pulmonary capillary wedge pressure (PCWP) is estimated using color M-mode Doppler study of left ventricular filling and Doppler tissue imaging. The goal of this study was to assess whether echocardiography accurately estimates PCWP in critically ill patients. METHODS: Sixty ventilated patients admitted for septic shock and acute lung injury were prospectively studied using simultaneously transesophageal echocardiography and pulmonary artery catheterization. Initial PCWP values and their changes measured invasively were compared to initial values and corresponding changes of early diastolic velocity of mitral annulus displacement measured by Doppler tissue imaging (Ea), flow propagation velocity of early diastolic mitral inflow measured by color M-mode Doppler (Vp), and their respective ratio to early mitral inflow velocity (E) measured by conventional Doppler: E/Ea and E/Vp. Relations between E/Ea, E/Vp, and PCWP were prospectively tested in 20 additional patients. RESULTS: E/Ea and E/Vp gave a rough estimate of initial PCWP values with mean biases of 0.4 +/- 2.2 and 0.1 +/- 2.9 mmHg, respectively. Receiving operating characteristic curves demonstrated that an E/Ea of 6 or greater is an accurate predictor of a PCWP of 13 mmHg or greater and that an E/Ea of 5.4 is a good predictor of a PCWP of 8 mmHg or less. Changes in PCWP were significantly correlated to changes in E/Ea (Rho = 0.84, P < 0.0001). CONCLUSIONS: In patients with postoperative circulatory shock and acute lung injury, transesophageal echocardiography estimates noninvasively PCWP. However, echocardiographic estimation of PCWP may not be accurate enough for adjusting therapy.