PubMed · 10636289
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G Barletta. 2000. Does flow reserve match contractility?. https://doi.org/10.1016/s0735-1097(99)00519-7
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Exercise electrocardiography (ECG) is of limited usefulness in hypertensive patients, whereas pharmacologic stress echocardiography can provide diagnostic and prognostic information. The aim of this study was to compare the prognostic value of clinical data, exercise ECG, and pharmacologic stress echocardiography in hypertensive patients with chest pain and to identify the best strategy for their risk stratification. Three hundred sixty-seven hypertensive patients (189 men, age 61 +/- 9 years) with chest pain of unknown origin underwent exercise ECG and pharmacologic stress echocardiography (237 with dipyridamole and 130 with dobutamine) and were followed up for 31 +/- 24 months. Positive exercise ECG (ST-segment shift of > or =1 mm at 80 ms after the J point) and stress echocardiography (new wall motion abnormalities) were found in 130 (35%) and 86 (23%) patients, respectively. During follow-up, there were 13 deaths and 16 myocardial infarctions. Additionally, 43 patients underwent coronary revascularization and were censored accordingly. Of 12 clinical, electrocardiographic, and echocardiographic variables analyzed, a positive result of stress echocardiography was the only multivariate predictor of either death (hazard ratio [HR] 4.7, 95% confidence interval [CI] 1.5 to 14.5, p = 0.007) or hard events (death, myocardial infarction) (HR 4.1, 95% CI 1.8 to 9.3, p = 0.0009). Using an interactive stepwise procedure, stress echocardiography provided additional prognostic information to clinical evaluation and exercise ECG. However, the negative predictive value of the 2 tests was similarly (p = NS) high in assessing 4-year event-free survival. In conclusion, a negative exercise electrocardiographic test identifies low-risk hypertensive patients with chest pain and should be the first-line approach for risk stratification. In contrast, positive exercise ECG is unable to distinguish between patients with different levels of risk. In this case, stress echocardiography provides strong and incremental prognostic power over clinical and exercise electrocardiographic data.
Several novel hydroxylated cis-decalin derivatives, potential intermediates for the synthesis of the AB ring system of the important cardiotonic steroid ouabain, have been synthesized from commercially available starting materials. The first step in the preparation of these highly functionalized intermediates is a Robinson annulation of the beta-keto ester 6 and the 4-silyl-3-buten-2-one 5 to furnish the octalone 4 with good diastereoselectivity in fair yield (due to competition with a novel silicon-to-carbon phenyl migration). Reduction of the epoxy alcohol 3 (derived from 4 in two high-yielding steps) with LiAlH(4) gave a mixture of the desired triol 11 along with the product of an unusual reductive opening at the tertiary carbon, namely the triol 12. A plausible mechanism for this unusual reduction is presented as are possible methods for avoiding it. In particular, reduction of the corrresponding epoxy ketone 15 with aluminum amalgam proceeded in good yield to give the hydroxy ketone 16. Also reduction of the epoxide ester having the inverted stereochemistry at C3 afforded the desired tertiary alcohol 33 in good yield. Another approach using the beta,gamma-unsaturated ketal 38 permitted the formation of the tertiary alcohol 40. Fleming oxidation of the related, very functionalized silane 39 afforded the desired 1beta-alcohol 41 in fair yield. Finally a novel rearrangement was observed when the epoxy alcohol 24 was treated with DIBAL to effect loss of the angular hydroxymethyl group to produce the tetrasubstitued alkene 29 in high yield.