Evaluation of the microcirculation in hypertension and cardiovascular disease.

The ability to investigate the microvascular structure and function is important in improving our understanding of pathophysiological processes in hypertension and related cardiovascular disease. A range of techniques are available or emerging for investigating different aspects of the microcirculation in animals and humans. Techniques such as experimental intravital microscopy and clinical intravital microscopy (e.g. orthogonal polarization spectral imaging) allow visualization at the level of single microvessels. Venous occlusion plethysmography can be used to measure blood flow in organs, and laser Doppler flowmetry to measure red cell flux in small areas of tissue. Positron emission tomography, myocardial contrast echocardiography, and magnetic resonance imaging provide three-dimensional imaging of local blood flow. The current and potential clinical usefulness of these different techniques is evaluated. The technical quality and availability for clinical use of some of the techniques should improve dramatically during the next few years. 'Molecular imaging'-the combination of these techniques with genetic, molecular, and computational approaches-offers great potential for use in research and in diagnosis and the monitoring of disease progression or the results of therapy. Closer attention to the microcirculation will ultimately improve the treatment and prevention of many of the most important forms of cardiovascular disease.