Use of ultrasound enhancing agents in transesophageal echocardiography to improve interpretive confidence of left atrial appendage thrombus.

BACKGROUND: The value of ultrasound enhancing agents (UEA) in patients undergoing transesophageal echocardiography (TEE) for the exclusion of left atrial appendage (LAA) thrombi prior to direct current cardioversion (DCCV) is evolving. METHODS: We retrospectively identified 88 consecutive TEEs, where a commercial UEA was used during LAA interrogation. De-identified non-enhanced (pre-UEA) and enhanced cine loop images (post-UEA) from the same subjects were randomly reviewed by four expert readers in a blinded fashion. RESULTS: In 33% of the cases, UEA use was associated with a statistically insignificant improvement in physician confidence (scale, 0-3) in determining the presence or absence of a LAA thrombus (P = 0.071). In instances where non-enhanced images yielded an uncertain interpretation or when the left atrium contained spontaneous echo contrast (SEC), UEA use was associated with an improvement in interpretive confidence in 49% (P < 0.001) and 41% of the cases (P = 0.001), respectively. Overall, the absolute rate of hypothetical decision to proceed with DCCV rose by 9% with the application of UEA (P = 0.004). In instances where non-enhanced images were interpreted with limited confidence or when SEC was present, there were absolute increases of 16% (P < 0.001) and 21% (P < 0.001) in hypothetical procession to DCCV, respectively. In cases of a combination of limited interpretive confidence and SEC, UEA use was associated with a 29% absolute increase in the rate of procession to DCCV (P < 0.001). CONCLUSIONS: In patients undergoing TEE interrogation of the LAA, the use of UEA is associated with an increase in the level of interpretive confidence and higher rates of theoretical procession to DCCV.

Increased TIMI frame counts in cocaine users: a case for increased microvascular resistance in the absence of epicardial coronary disease or spasm.

BACKGROUND: Cocaine produces adverse cardiovascular effects, some of which cannot be explained by epicardial coronary artery disease (CAD) or spasm. HYPOTHESIS: The hypothesis of this study was that cocaine users would have increased coronary microvascular resistance, even in the absence of recent myocardial infarction (MI), CAD, or spasm. METHODS: Microvascular resistance was assessed by the corrected Thrombolysis in Myocardial Infarction (TIMI) frame count (cTFC) method in a consecutive series of 59 cocaine users without acute or recent MI or angiographically significant epicardial stenosis (> 50%) or spasm. The cTFCs in these patients were compared with 21 normal controls and with published normal cTFC values. RESULTS: The cTFC was significantly elevated (by 26-54%) in cocaine users. The cTFCs in the left anterior descending (LAD), circumflex (LCx), and right coronary (RCA)arteries in cocaine users were 30.0 +/- 10.9,34.1 +/- 11.5, and 28.6 +/- 11.8, respectively, compared with values in normal controls of 21.3 +/- 4.3 (p = 0.001), 24.4 +/- 7.2 (p = 0.001), and 22.7 +/- 5.1 (p = 0.04), respectively, and published normal cTFC values (all p < 0.01). An abnormally high cTFC was present in 61% of patients in the LAD, 69% in the LCx, and 47% in the RCA. CONCLUSIONS: Markedly decreased coronary blood flow velocity, indicating increased microvascular resistance, is present in cocaine users, even in the absence of acute or recent MI, or significant epicardial CAD or spasm. Increased microvascular resistance may explain many important cardiovascular manifestations of cocaine use and has therapeutic implications. Slow coronary filling may also suggest the possibility of cocaine use in patients in whom it was not otherwise suspected.

A novel, accelerated method of desensitization in a patient with a documented hypersensitivity reaction to clopidogrel.

Current standard of care following a percutaneous coronary intervention with stent placement necessitates the use of dual anti-platelet therapy with aspirin and commonly clopidogrel. There is a subset of patients who have a significant clopidogrel allergy and life-threatening hypersensitivity reactions. Desensitization is the process of inducing tolerance to a sensitizing agent via repeated exposure to the agent. There have been previously reported protocols for clopidogrel desensitization. These protocols differ in length and dose escalation and a universally accepted clopidogrel desensitization protocol has yet to be established. We discuss here a novel accelerated approach to clopidogrel desensitization in a patient with a documented hypersensitivity reaction.