Safety of thrombolytic therapy in elderly patients with massive pulmonary embolism: a comparison with nonelderly patients.

Objectives: The aim of the study was to prospectively estimate the safety of thrombolytic therapy in elderly patients with massive pulmonary embolism in comparison with that in nonelderly patients.

Background: In massive pulmonary embolism, lysis of thrombi can be achieved faster with thrombolytic therapy than with conventional heparin therapy, but it is administered with great caution in elderly patients because the risk of bleeding is thought to be higher than in nonelderly patients. Yet, thrombolytic therapy might be of value in elderly patients also, in allowing potentially more rapid improvement than is achieved with conventional heparin therapy.

[Instantaneous pressure-velocity relationship of the coronary flow, alternative to coronary reserve measurement: a feasibility study and reproducibility of the method].

Animal experimentation has shown that the instantaneous pressure-velocity of coronary blood flow in the hyperaemic phase has a linear relationship. The slope of this regression evaluates coronary reserve independently of haemodynamic variables and the X-intercept (zero flow pressure or Pf = 0) determines the intra-myocardial back pressure which could influence the regulation of coronary flow. The object of this study was to evaluate the instantaneous pressure-velocity relationship of coronary flow in clinical practice and to analyse the reproducibility of this parameter.

Maximal blood flow velocity in severe coronary stenoses measured with a Doppler guidewire. Limitations for the application of the continuity equation in the assessment of stenosis severity.

In vitro and animal experiments have shown that the severity of coronary stenoses can be assessed using the continuity equation if the maximal blood flow velocity of the stenotic jet is measured. The large diameter and the low range of velocities measurable without frequency aliasing with the conventional intracoronary Doppler catheters precluded the clinical application of this method for hemodynamically significant coronary stenoses in humans. This article reports the results obtained using a 12 MHz steerable angioplasty guidewire in a consecutive series of 52 patients undergoing percutaneous coronary angioplasty (61 coronary stenoses).

Intracoronary pressure and flow velocity with sensor-tip guidewires: a new methodologic approach for assessment of coronary hemodynamics before and after coronary interventions.

The use of miniaturized pressure and velocity sensors mounted on angioplasty guidewires allows the simultaneous measurement of coronary blood flow velocity and transstenotic pressure gradient, 2 parameters that, combined, should perfectly characterize stenosis hemodynamics. The aim of this article is assessment of the changes in coronary blood flow velocity observed with a Doppler-tipped angioplasty guidewire in 35 patients undergoing balloon angioplasty. We also report our initial experience in 16 patients with the combined use of sensor-tip pressure and Doppler guidewires, and we discuss the application of new methodologic approaches for the study of the coronary circulation allowed by these techniques, such as the instantaneous assessment of the flow velocity/pressure and pressure gradient/flow velocity relations.