Enhanced coronary blood flow velocity during intraaortic balloon counterpulsation in critically ill patients.

OBJECTIVES: The aim of this study was to assess coronary blood flow during intraaortic balloon counterpulsation by direct measurement. BACKGROUND: In a majority of human studies, increased coronary blood flow during intraaortic balloon counterpulsation measured by indirect techniques has not been consistently demonstrated. METHODS: Hemodynamic variables and coronary blood flow velocity (20-MHz Doppler-tipped catheter) data were measured in 19 patients requiring intraaortic balloon pumping for clinical indications (11 patients had acute myocardial infarction [9 with shock], 6 had unstable angina, 1 had acute mitral regurgitation and 1 was at high risk undergoing angioplasty). Hemodynamic data, mean and phasic diastolic flow velocity and velocity-time integrals (computed from digitized waveforms) were analyzed during periods of 1:1 balloon counterpulsation. RESULTS: Intraaortic balloon pumping decreased systolic pressure (6 +/- 10%, p < 0.001) and increased diastolic pressure (80 +/- 30% from baseline, p < 0.001) without changing RR interval. Peak phasic, mean coronary flow velocity and diastolic flow velocity integral were significantly increased (115 +/- 115%, 67 +/- 61%, 103 +/- 81%, respectively, all p < 0.001) during intraaortic balloon pumping. In addition, although a wide splay of data was evident due to operator set variations in balloon inflation and deflation timing, the greater increases in diastolic flow velocity integral (DFVi) occurred in patients with basal systolic pressure < or = 90 mm Hg (% delta DFVi = 102 - 0.1.[unaugmented systolic pressure], SEE = 21.7 mm Hg, r = 0.30, p < 0.001). CONCLUSIONS: Intraaortic balloon pumping unequivocally and significantly augments proximal coronary blood flow velocity, nearly doubling the coronary flow velocity integral in most patients. This mechanism may be a significant means of ischemia relief in hypotensive patients.

Effects of percutaneous transluminal coronary angioplasty balloon compliance on angiographic and clinical outcomes.

The effect of balloon compliance on the safety and outcome of percutaneous transluminal coronary angioplasty (PTCA) is controversial. It has been proposed that PTCA balloons constructed from compliant polymers contribute to an increased risk of angiographic coronary dissection and potentially to adverse clinical results. To determine the effect of balloon material compliance on PTCA outcome, 1,076 PTCA procedures using balloons differing in compliance characteristics (polyethylene teraphthalate [noncompliant], polyethylene [intermediately compliant] or polyolefincopolymer [compliant]) were retrospectively analyzed. Baseline clinical, angiographic and procedural variables were similar among the 3 balloon material groups. In the noncompliant, intermediately compliant and compliant groups, the occurrence rates of intimal tears (10, 14 and 10%, respectively; p = NS for all comparisons) and coronary dissection (7, 9 and 8%, respectively; all p = NS) were also equivalent. The rates of acute occlusion, myocardial infarction, emergency bypass surgery and death were low and similar, and likewise unaffected by balloon material. The results provide evidence that the occurrence of adverse outcomes after PTCA is unrelated to balloon material compliance and support the clinical safety of balloons constructed of compliant or noncompliant polymers when used for appropriate coronary interventions.

Two-dimensional, spectral Doppler, and color flow imaging in adults with acquired and congenital cor triatriatum.

Four adult patients ranging in age from 37 to 72 years with cor triatriatum diagnosed by two-dimensional, spectral Doppler, and color flow imaging are presented, including a previously undescribed "acquired" form after orthotopic heart transplantation and the oldest documented patient with cor triatriatum. The echocardiographic features of cor triatriatum with use of surface and transesophageal imaging are reviewed, with particular emphasis on the color flow findings. Color flow imaging has simplified the diagnosis and assessment of cor triatriatum, including the demonstration of other often-associated congenital cardiac anomalies.

Sequence analysis of the ZFY and Sox genes in the turtle, Chelydra serpentina.

We have sequenced regions of the ZFY and Sox genes in the turtle Chelydra serpentina, a reptile with temperature-dependent sex determination. The ZFY gene in mammals encodes a transcription factor with multiple zinc fingers that may be involved in spermatogenesis as well as other processes. The turtle homologue, Zft, is 92% identical to the ZFY gene at the nucleotide and amino acid levels in the region of zinc fingers 7-12. There are several Sox genes in the turtle that are only 57-70% identical at the nucleotide level and about 55% identical at the amino acid level to the human sex-determining SRY gene. However, the turtle Sox genes, termed TSox, have the conserved motif called the HMG-box (for high mobility group DNA-binding protein) that defines a probable DNA-binding region, and thus are in the same gene family as the Sox genes of other organisms from Drosophila to man. One TSox sequence is identical at the amino acid level to a sequence found in birds, and is 98% identical to a sequence encoded autosomally in mouse and in man. The extent of sequence conservation among the Sox genes suggests that some of their functions may be conserved. Phylogenetic analysis of available Sox sequences including SRY (Sry) sequences suggests that there was a high degree of divergence between any possible immediate common ancestor of the turtle Sox sequences and the SRY (Sry) sequences.

Thermal independence of muscle tissue metabolism in the leatherback turtle, Dermochelys coriacea.

Metabolic rates of animal tissues typically increase with increasing temperature and thermoregulatory control in an animal is a regional or whole body process. Here we report that metabolic rates of isolated leatherback turtle (Dermochelys coriacea) pectoralis muscle are independent of temperature from 5-38 degrees C (Q10 = 1). Conversely, metabolic rates of green turtle (Chelonia mydas) pectoralis muscle exhibit a typical vertebrate response and increase with increasing temperature (Q10 = 1.3-3.0). Leatherbacks traverse oceanic waters with dramatic temperature differences during their migrations from sub-polar to equatorial regions. The metabolic stability of leatherback muscle effectively uncouples resting muscle metabolism from thermal constraints typical of other vertebrate tissues. Unique muscle physiology of leatherbacks has important implications for understanding vertebrate muscle function, and is another strong argument for preservation of this endangered species.

Superior accuracy of anatomic positioning with echocardiographic- over fluoroscopic-guided endomyocardial biopsy.

To assess the superior anatomic positioning of echocardiographic-guided endomyocardial biopsy compared to traditional fluoroscopic-guided technique, these two modalities were compared in a blinded fashion during femoral sheath endomyocardial biopsy in 21 patients, 19 being evaluated after orthotopic cardiac transplantation. The simultaneous fluoroscopic and echocardiographic imaging indicated that traditional fluoroscopic positioning of the bioptome against the septum is inaccurate in over half of patients undergoing biopsy. This finding should be considered in cardiomyopathy patients or those at high risk for biopsy-related complications.