Prognostic implications of asymptomatic left ventricular dysfunction in patients undergoing vascular surgery

Background: The prognostic value of heart failure symptoms on postoperative outcome is well acknowledged in perioperative guidelines. The prognostic value of asymptomatic left ventricular (LV) dysfunction remains unknown. This study evaluated the prognostic implications of asymptomatic LV dysfunction in vascular surgery patients assessed with routine echocardiography. Methods: Echocardiography was performed preoperatively in 1,005 consecutive vascular surgery patients. Systolic LV dysfunction was defined as LV ejection fraction less than 50%. Ratio of mitral-peak velocity during early and late filling, pulmonary vein flow, and deceleration time was used to diagnose diastolic LV dysfunction. Troponin-T measurements and electrocardiograms were performed routinely perioperatively. Multivariate regression analyses evaluated the relation between LV function and the study endpoints, 30-day cardiovascular events, and long-term cardiovascular mortality. Results: Left ventricular dysfunction was diagnosed in 506 (50%) patients of which 80% were asymptomatic. In open vascular surgery (n = 649), both asymptomatic systolic and isolated diastolic LV dysfunctions were associated with 30-day cardiovascular events (odds ratios 2.3, 95% confidence interval [CI] 1.4-3.6 and 1.8, 95% CI 1.1-2.9, respectively) and long-term cardiovascular mortality (hazard ratios 4.6, 95% CI 2.4-8.5 and 3.0, 95% CI 1.5-6.0, respectively). In endovascular surgery (n = 356), only symptomatic heart failure was associated with 30-day cardiovascular events (odds ratio 1.8, 95% CI 1.1-2.9) and long-term cardiovascular mortality (hazard ratio 10.3, 95% CI 5.4-19.3). Conclusions: This study demonstrated that asymptomatic LV dysfunction is predictive for 30-day and long-term cardiovascular outcome in open vascular surgery patients. These data suggest that preoperative risk stratification should include not only solely heart failure symptoms but also routine preoperative echocardiography to risk stratify open vascular surgery patients. Copyrigh

Filocrono em batateira afetado pelo tamanho do tubérculo-semente e pela época de cultivo Phyllocrono in potato affected by tuber-seed size and growing season

O objetivo deste trabalho foi estimar o filocrono de plantas de batata da cultivar Asterix oriundas de diferentes tamanhos de tubérculos-semente, em duas épocas de cultivo em campo utilizando o conceito de graus-dia para o cálculo do filocrono. O experimento foi desenvolvido em Santa Maria (RS), na primavera de 2003 e no outono de 2004. Foram usados quatro tamanhos de tubérculos-semente da cultivar de batata Asterix: entre 2 e 4 cm, 4 e 6 cm, 6 e 8 cm e 8 e 10 cm. O filocrono (ºC dia folha-1) foi estimado pelo inverso do coeficiente angular da relação entre número de folhas na haste principal e a soma térmica calculada por três métodos: método 1 - considera apenas a temperatura base; método 2 - considera a temperatura base e a temperatura ótima, e método 3 - considera a temperatura base, a temperatura ótima e a temperatura máxima. O tamanho do tubérculo-semente não afetou o filocrono, mas o método de cálculo da soma térmica e a época de cultivo afetaram o filocrono da batateira cultivar Asterix. No método de cálculo da soma térmica a ser usado no filocrono da batateira cultivar Asterix, recomenda-se usar a temperatura base e a temperatura ótima, pois com este método, o filocrono foi similar entre as épocas de cultivo.<br>The objective of this study was to estimate the phyllochron of the potato cultivar Asterix in plants derived from different tuber seed sizes in two field growing seasons using the concept of degrees-days for calculating the phyllochron. The experiment was conducted in Santa Maria, RS, during Spring 2003 and Fall 2004. Four classes of tuber-seed diameter of the potato cultivar Asterix were used: 2-4 cm, 4-6 cm, 6-8 cm and 8-10 cm. The phyllochron was estimated as the inverse of the slope of the linear regression of main stem leaves number against the thermal time calculated with three methods: method 1 - considering only the base temperature, method 2 - considering the base temperature and the optimum temperature, and method 3 - considering the base temperature, the optimum temperature and the maximum temperature. Tuber-seed size did not affect the phyllochron of the potato cultivar Asterix, but the method of calculating thermal time and the planting date affected the phyllochron. For the method of calculating thermal time in the phyllochron of the potato cultivar Asterix, it is recommended to use the base temperature and the optimum temperature, because it produced similar phyllochron values in the two growing seasons