Speciality
Spotlight

 




 


Cardiology


 


   





Coronary Artery
Surgery

    

  • Mangano CM, for the Multicenter Study of Perioperative Ischemia Research Group [Stanford Univ, Calif; Ischemia Research and Education Found, San Fransisco; Emory Univ, Atlanta, Ga; et al]

    Renal Dysfunction After Myocardial Revascularization : Risk Factors, Outcomes, and Hospital Resource Utilization

    Ann Intern Med 128: 194-203, 1998



    The effects of cardiac surgery on renal function remain unclear. Renal function abnormalities can result from nonpulsatile flow, increased catecholamine and inflammatory mediator levels, renal embolic insults, and release of free hemoglobin from traumatized erythrocytes. Renal dysfunction was studied in a large population of patients undergoing cardiopulmonary bypass and myocardial revascularization.



    A total of 2,222 patients undergoing myocardial revascularization at 24 research hospitals were studied. Their rates of postoperative renal failure [defined as need for dialysis] and of renal dysfunction [defined as a postoperative serum creatinine level of 2.0 mg/dL or greater and an increase in serum creatinine of 0.7 mg/dL or greater from the preoperative level ] were assessed. 



    By these definitions, postoperative dysfunction occurred in 7.7% of patients and renal failure in 1.4%. Mortality was 0.9% patients with neither adverse renal outcome, compared with 19% for those with renal dysfunction and 63% for those with renal failure. The risk of renal failure increased steadily with age: doubled for patients in their 70s and tripled for those in their 80s, compared with younger patients, Factors associated with renal dysfunction, were type 1 diabetes mellitus, preoperative glucose level, congestive heart failure, previous coronary artery bypass grafting, and postoperative creatinine level of 2.0 mg/dL. More than 80% of patients with renal dysfunction had intraoperative or postoperative hemodynamic instability or hemorrhage. 



    An 8% rate of renal dysfunction or failure was documented in patients undergoing myocardial revascularization. Renal risk is related to patient -specific factors, probably reflecting diffuse atherosclerosis. The findings have implications for preoperative communication of risk, treatment with potential nephrotoxic drugs, and surgical technique.

  • Laeur MS, Lytle B, Pashkow F, et al [ Cleveland Clinic Found, Ohio]

    Prediction of Death and Myocardial Infarction by Screening with Exercise-Thallium Testing After Coronary Artery Bypass Grafting

    Lancet 351: 615-622, 1998



    Coronary artery bypass grafting is becoming more common in the treatment of patients with coronary heart disease. The value of myocardial-perfusion imaging in determining risk in patients without symptoms after coronary artery bypass grafting is controversial. Clinical guidelines of the American Heart Association/ American College of Cardiology do not recommend routine screening of such patients but do allow for screening of selected patients without symptoms.



    The independent and incremental value of exercise thallium-201 single-photon emission CT in predicting death and nonfatal myocardial infarction was determined in 873 patients. The mean patient age was 64 years; 9% were women. All patients had undergone coronary artery bypass grafting, and none had recurrent angina or other major coronary events. Follow-up was 3 years. 



    Aanalysis showed that 508 patients had myocardial-perfusion defects, 57 died and 72 experienced major events. Patients with thallium-perfusion defects had a higher rate of death and of major events. Fixed defects only were not associated with risk of death or major events. Reversible defects were associated with death and major events and with higher event rates in low-risk and high-risk patients. Impaired exercise capacity was the exercise variable with the strongest predictive power; poor exercise capacity was predictive of death. [18% vs 4%] and death or nonfatal myocardial infarction [19% vs 5%]. The sensitivity of thallium-perfusion defects for predicting major events was 82%; specificity was 43%; positive predictive value was 15%, and negative predictive value was 95%. The sensitivity of reversible thallium-perfusion defects was 36%; specificity was 80%; positive predictive value was 18%, and negative predictive value was 91%. In these patients, thallium-perfusion defects and impaired exercise capacity were strong predictors of death or nonfatal myocardial infarction. Based on these findings, it is recommended that the current guidelines against routine screening with myocardial-perfusion tests in patients without symptoms after coronary artery bypass grafting be reconsidered      

                              
  • Pratt JW, Williams TE, Michler RE, et al (Ohio State Univ, Columbus)

    Current Indications for Left Thoracotomy in Coronary Revascularization and Valvular Procedures

    Ann Thorac Surg 70: 1366-1370, 2000

                                                       

    Left thoracotomy is rarely used in cardiac procedures. Recently it has been used in reoperation and minimally invasive coronary revascularization and in valvular procedures. 

                                  

    Authors report 3 cases after review of literature, with unique benefits of this approach for myocardial revascularization and valve replacement and conclude that left thoracotomy is an alternate approach to median sternotomy. Two important requisites in this approach are                                 

    1) double-lumen endotracheal intubation to allow collapse of the left lung for better exposure and 

    2) placement of an epidural anaesthesia catheter at completion of the procedure for post-operative pain management.     

                         
  • Borst C (Utrecht Univ, The Netherlands)                

    Operating on a Beating Heart                         

    Sci Am October: 58-63, 2000               

                                                                                          

    Coronary bypass surgery is common but it is risky and expensive. Cardiopulmonary bypass has its own complications. One third of all patients have operative complications and the risk rises in the elderly and debilitated patients. In the early 1990s researchers began developing techniques for operating on the beating heart.   

                                                                                   

    To operate on a beating heart, the portion of the heart on which the operation is to be performed, has to be stabilized; the Octopus stabilizer was thus developed in 1995. Initial results show fewer complications, lesser blood transfusions, less time in the ICU, earlier hospital discharge and lower costs.                 

                                      
  • Kshettry
    VR, Flavin TF, Emery RW, et al (Minneapolis Heart Inst)         

    Does Multivessel, Off-Pump Coronary Artery Bypass Grafting Reduce Postoperative Morbidity?     

    Ann Thorac Surg 69: 1725-1731, 2000                                 

                                                                                    

    Cardiopulmonary Bypass (CPB) with cardioplegic cardiac arrest is the common method for performing coronary artery bypass grafting
    (CABG). Recently CABG is being increasingly done on the beating heart
    (OPCABG) to reduce complications. The safety and efficacy of the two systems are compared.        

                                

    Reviewed were 744 patients who underwent CABG with 3 or more distal
    anastomoses, between 1979 and 1999. There were 609 operated with CPB and 135 with
    OPCABG. 

                         

    The average risk-adjusted predicted mortality was same in both groups, as also major postoperative complications. Blood loss and transfusions were significantly greater in the CPB group.

                              

    The results of this retrospective non-randomized review indicate that OPCABG can be performed safely and effectively but with no reduction in postoperative complications.             


        




 

 

Speciality Spotlight

 

   

Coronary Artery Surgery
    

  • Mangano CM, for the Multicenter Study of Perioperative Ischemia Research Group [Stanford Univ, Calif; Ischemia Research and Education Found, San Fransisco; Emory Univ, Atlanta, Ga; et al]
    Renal Dysfunction After Myocardial Revascularization : Risk Factors, Outcomes, and Hospital Resource Utilization
    Ann Intern Med 128: 194-203, 1998

    The effects of cardiac surgery on renal function remain unclear. Renal function abnormalities can result from nonpulsatile flow, increased catecholamine and inflammatory mediator levels, renal embolic insults, and release of free hemoglobin from traumatized erythrocytes. Renal dysfunction was studied in a large population of patients undergoing cardiopulmonary bypass and myocardial revascularization.

    A total of 2,222 patients undergoing myocardial revascularization at 24 research hospitals were studied. Their rates of postoperative renal failure [defined as need for dialysis] and of renal dysfunction [defined as a postoperative serum creatinine level of 2.0 mg/dL or greater and an increase in serum creatinine of 0.7 mg/dL or greater from the preoperative level ] were assessed. 

    By these definitions, postoperative dysfunction occurred in 7.7% of patients and renal failure in 1.4%. Mortality was 0.9% patients with neither adverse renal outcome, compared with 19% for those with renal dysfunction and 63% for those with renal failure. The risk of renal failure increased steadily with age: doubled for patients in their 70s and tripled for those in their 80s, compared with younger patients, Factors associated with renal dysfunction, were type 1 diabetes mellitus, preoperative glucose level, congestive heart failure, previous coronary artery bypass grafting, and postoperative creatinine level of 2.0 mg/dL. More than 80% of patients with renal dysfunction had intraoperative or postoperative hemodynamic instability or hemorrhage. 

    An 8% rate of renal dysfunction or failure was documented in patients undergoing myocardial revascularization. Renal risk is related to patient -specific factors, probably reflecting diffuse atherosclerosis. The findings have implications for preoperative communication of risk, treatment with potential nephrotoxic drugs, and surgical technique.
  • Laeur MS, Lytle B, Pashkow F, et al [ Cleveland Clinic Found, Ohio]
    Prediction of Death and Myocardial Infarction by Screening with Exercise-Thallium Testing After Coronary Artery Bypass Grafting
    Lancet 351: 615-622, 1998

    Coronary artery bypass grafting is becoming more common in the treatment of patients with coronary heart disease. The value of myocardial-perfusion imaging in determining risk in patients without symptoms after coronary artery bypass grafting is controversial. Clinical guidelines of the American Heart Association/ American College of Cardiology do not recommend routine screening of such patients but do allow for screening of selected patients without symptoms.

    The independent and incremental value of exercise thallium-201 single-photon emission CT in predicting death and nonfatal myocardial infarction was determined in 873 patients. The mean patient age was 64 years; 9% were women. All patients had undergone coronary artery bypass grafting, and none had recurrent angina or other major coronary events. Follow-up was 3 years. 

    Aanalysis showed that 508 patients had myocardial-perfusion defects, 57 died and 72 experienced major events. Patients with thallium-perfusion defects had a higher rate of death and of major events. Fixed defects only were not associated with risk of death or major events. Reversible defects were associated with death and major events and with higher event rates in low-risk and high-risk patients. Impaired exercise capacity was the exercise variable with the strongest predictive power; poor exercise capacity was predictive of death. [18% vs 4%] and death or nonfatal myocardial infarction [19% vs 5%]. The sensitivity of thallium-perfusion defects for predicting major events was 82%; specificity was 43%; positive predictive value was 15%, and negative predictive value was 95%. The sensitivity of reversible thallium-perfusion defects was 36%; specificity was 80%; positive predictive value was 18%, and negative predictive value was 91%. In these patients, thallium-perfusion defects and impaired exercise capacity were strong predictors of death or nonfatal myocardial infarction. Based on these findings, it is recommended that the current guidelines against routine screening with myocardial-perfusion tests in patients without symptoms after coronary artery bypass grafting be reconsidered      
                              
  • Pratt JW, Williams TE, Michler RE, et al (Ohio State Univ, Columbus)
    Current Indications for Left Thoracotomy in Coronary Revascularization and Valvular Procedures
    Ann Thorac Surg 70: 1366-1370, 2000
                                                       
    Left thoracotomy is rarely used in cardiac procedures. Recently it has been used in reoperation and minimally invasive coronary revascularization and in valvular procedures. 
                                  
    Authors report 3 cases after review of literature, with unique benefits of this approach for myocardial revascularization and valve replacement and conclude that left thoracotomy is an alternate approach to median sternotomy. Two important requisites in this approach are                                 
    1) double-lumen endotracheal intubation to allow collapse of the left lung for better exposure and 
    2) placement of an epidural anaesthesia catheter at completion of the procedure for post-operative pain management.     
                         
  • Borst C (Utrecht Univ, The Netherlands)                
    Operating on a Beating Heart                         
    Sci Am October: 58-63, 2000               
                                                                                          
    Coronary bypass surgery is common but it is risky and expensive. Cardiopulmonary bypass has its own complications. One third of all patients have operative complications and the risk rises in the elderly and debilitated patients. In the early 1990s researchers began developing techniques for operating on the beating heart.   
                                                                                   
    To operate on a beating heart, the portion of the heart on which the operation is to be performed, has to be stabilized; the Octopus stabilizer was thus developed in 1995. Initial results show fewer complications, lesser blood transfusions, less time in the ICU, earlier hospital discharge and lower costs.                 
                                      
  • Kshettry VR, Flavin TF, Emery RW, et al (Minneapolis Heart Inst)         
    Does Multivessel, Off-Pump Coronary Artery Bypass Grafting Reduce Postoperative Morbidity?     
    Ann Thorac Surg 69: 1725-1731, 2000                                 
                                                                                    
    Cardiopulmonary Bypass (CPB) with cardioplegic cardiac arrest is the common method for performing coronary artery bypass grafting (CABG). Recently CABG is being increasingly done on the beating heart (OPCABG) to reduce complications. The safety and efficacy of the two systems are compared.        
                                
    Reviewed were 744 patients who underwent CABG with 3 or more distal anastomoses, between 1979 and 1999. There were 609 operated with CPB and 135 with OPCABG. 
                         
    The average risk-adjusted predicted mortality was same in both groups, as also major postoperative complications. Blood loss and transfusions were significantly greater in the CPB group.
                              
    The results of this retrospective non-randomized review indicate that OPCABG can be performed safely and effectively but with no reduction in postoperative complications.             
        

 

By |2022-07-20T16:44:10+00:00July 20, 2022|Uncategorized|Comments Off on Coronary Artery Surgery

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