Cardiogenic shock complicating acute myocardial infarction: The use of coronary angioplasty and the integration of the new support devices into patient management

Conventional therapy for cardiogenic shock complicating acute myocardial infarction continues to be associated with a high in-hospital mortality rate. Hemodynamic support with new mechanical devices and emergency coronary revascularization may alter the long-term prognosis for patients with this complication. Between July 1985 and March 1990, 68 patients presented to the University of Michigan with acute myocardial infarction and cardiogenic shock. Interventions performed included thrombolytic therapy (46%), intraaortic balloon pump counterpulsation (70%), cardiac catheterization (86%), coronary angioplasty (73%), emergency coronary artery bypass grafting/ventricular septal defect repair (15%), Hemopump insertion (11%), percutaneous cardiopulmonary support (4%) and ventricular assist device (3%).The 30-day survival rate was significantly better in patients who had successful angioplasty of the infarct-related artery than in patients with failed angioplasty (61% vs. 7%, p = 0.002) or no attempt at angioplasty (61% vs. 14%, p = 0.003). This difference was maintained over the 1-year follow-up period. The only clinical variable that predicted survival was age <65 years.The early use of the new support devices in 10 patients was associated with death in 8 (80%), but this poor outcome may reflect a selection bias for an especially high risk population. Collectively, these recent data continue to suggest that emergency revascularization with angioplasty may reduce the mortality rate, but further study is required to define optimal utilization and integration of new support devices

Complete atrioventricular block complicating inferior wall acute myocardial infarction treated with reperfusion therapy

Previous studies report larger myocardial infants and increased in-hospital mortality rates in patients with inferior wall acute myocardial infarction (AMI) and complete atrioventricular block (AV), but the clinical implications of these complications in patients treated with reperfusion therapy have not been addressed. The clinical course of 373 patients--50 (13%) of whom developed complete AV block--admitted with inferior wall AMI and given thrombolytic therapy within 6 hours of symptom onset was studied. Acute patency rates of the infarct artery after thrombolytic therapy were similar in patients with or without AV block. Ventricular function measured at baseline and before discharge in patients with complete AV block showed a decrement in median ejection fraction (-3.5 vs -0.4%, P = 0.03) and in median regional wall motion (-0.14 vs +0.24 standard deviations/chord, P = 0.05). The reocclusion rate was higher in patients with complete AV block (29 vs 16%, P = 0.03). Patients with complete AV block had more episodes of ventricular fibrillation or tachycardia (36 vs 14%, p &lt; 0.001), sustained hypotension (36 vs 10%, p &lt; 0.001), pulmonary edema (12 vs 4%, P = 0.02) and a higher in-hospital mortality rate (20 vs 4%, p &lt; 0.001), although the mortality rate after hospital discharge was identical (2%) in the 2 groups. Multivariable logistic regression analysis revealed that complete AV block was a strong independent predictor of in-hospital mortality (p = 0.0006). Thus, despite initial successful reperfusion, patients with inferior wall AMI and complete AV block have higher rates of in-hospital complications and mortality.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29481/1/0000567.pd

Comparison of rubidium-82 positron emission tomography and thallium-201 SPECT imaging for detection of coronary artery disease

The diagnostic performance of rubidium-82 (Rb-82) positron emission tomography (PET) and thallium-201 (TI-201) single-photon emission-computed tomography (SPECT) for detecting coronary artery disease was investigated in 81 patients (52 men, 29 women). PET studies using 60 mCi of Rb-82 were performed at baseline and after intravenous infusion of 0.56 mg/kg dipyridamole in conjunction with handgrip stress. TI-201 SPECT was performed after dipyridamole-handgrip stress and, in a subset of patients, after treadmill exercise. Sensitivity, specificity and overall diagnostic accuracy were assessed using both visually and quantitatively interpreted coronary angiograms. The overall sensitivity, specificity and accuracy of PET for detection of coronary artery disease (&gt;50% diameter stenosis) were 84,88 and 85%, respectively. In comparison, the performance of SPECT revealed a sensitivity of 84%, specificity of 53% (p &lt; 0.05 vs PET) and accuracy of 79%. Similar results were obtained using either visual or quantitative angiographic criteria for severity of coronary artery disease. In 43 patients without prior myocardial infarction, the sensitivity for detection of disease was 71 and 73%, respectively, similar for both PET and SPECT. There was no significant difference in diagnostic performance between imaging modalities when 2 different modes of stress (exercise treadmill vs intravenous dipyridamole plus handgrip) were used with SPECT imaging. Thus, Rb-82 PET provides improved specificity compared with TI-201 SPECT for identifying coronary artery disease, most likely due to the higher photon energy of Rb-82 and attenuation correction provided by PET. However, post-test referral cannot be entirely excluded as a potential explanation for the lower specificity of TI-201 SPECT.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29280/1/0000339.pd

Comparison of thallium-201 SPECT redistribution patterns and rubidium-82 PET rest-stress myocardial blood flow imaging

To compare regional thallium-201 SPECT redistribution patterns with rubidium-82 PET, we studied 81 patients with both imaging modalities. Sixty patients had significant coronary artery disease. All patients underwent PET imaging after dipyridamole infusion, while SPECT imaging was performed after exercise stress (38 patients) and dipyridamole (43 patients). Sixty-eight percent of patients with prior infarct had fixed defects on SPECT, compared to 39% with PET. Sixty-one percent of patients with prior infarct had PET perfusion defects which exhibited ‘reflow’ or normal rubidium-82 tracer uptake (p < 0.05 vs. SPECT). Similar results were seen in patients without prior infarct (26% fixed defects on SPECT vs. 12% for PET, p < 0.05). Regional analysis showed that 57% of fixed SPECT defects corresponded to PET defects with reflow or normal rubidium-82 uptake, while 78% of ‘fixed’ PET defects corresponded to fixed SPECT defects. PET reflow and normal rubidium-82 uptake in sites of fixed thallium-201 SPECT perfusion defects suggest that imaging modalities employing separate tracer injections at rest and after stress, such as rubidium-82 PET, may be more specific in the assessment of myocardial viability, especially in patients with prior myocardial infarction.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42537/1/10554_2005_Article_BF01151577.pd

High Sensitivity Troponin at RRHS

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