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The use of Digital Subtraction Angiography in coronary applications is restricted by the difficulty in: 1. Obtaining a good resolution of the distal branches. 2. Avoiding, for the purpose of subtraction, the motion artifacts induced by artery and background displacement during the cardiac and respiratory cycles. 3. Preserving the dynamic vascular motion. 4. And storing the digital dynamic information on a permanent support. We used for this study an angiography system, based upon a high resolution 45 MIPS-32 Mbyte image processor, interfaced with a 2.75 Gbyte Winchester drive allowing the real time storage of either 30 frames/s in the 512*512*8 bits matrix or of 7.5 f/s in the 1024*1024*8 bits matrix. To preserve the most important dynamic informations on the basis of the 7.5 f/s maximal storage rate, we developed a synchronization device able to recognize in real time, from chronologic delays derived by using both ECG and Aortic Pressure curves, the functional End-Diastolic (ED) and the End-Systolic (ES) positions, even in the case of heart rates varying during the procedure. The ED and the ES images are stored together with the Mid-Systolic (MS), the 1/3-Diastolic (1/3D) and 2/3-Diastolic (2/3D) images. To establish the validity of this sampling method, which uses a reduced number of frames per cardiac cycle, 7200 coronary injections performed during 450 routine coronary angiographies were compared by two independent observers (A and B), using: first a Digital (D) 5 frames/cycle sequence, and secondly a cine Film (F) 50 frames/s sequence acquired immediately after the corresponding D injection. The D technique resulted in the best image and diagnostic quality, particularly when the F quality was estimated 'fair' or 'poor' by both observers, and in an important reduction on X-Ray doses. The visualisation of the sequential ED, MS, ES, 1/3D and 2/3D frames gives the possibility: 1. of saving the dynamic information, as a regular sample of functional images can be displayed with a cine loop technique. 2. of facilitating cardiac synchronized subtractions. 3. of reducing the amount of frames per cycle, thus allowing an important reduction of X-ray doses and the digital and permanent storage of the most important cardiac cycles.

The large arterial system and the microcirculatory network are generally studied as separated entities. We aimed to establish a link between the remodelling of microcirculatory and arterial blood pressure. Experimental Pre-hypertensive spontaneously hypertensive rats SHRs were maintained under hypoxic (12% O 2 ) conditions for 8 weeks. The systolic blood pressure was lower by 26% in hypoxic vs. normoxic SHRs. Total peripheral vascular resistance was 30% lower in hypoxic than in normoxic SHRs. At the end of the hypoxic period, capillary density in skeletal muscle was 1.2-fold higher in hypoxic than in normoxic SHRs. Myocardial capillary density and VEGF-A protein contents were also 1.2- and 2.1-fold higher in hypoxic compared to normoxic SHRs. Thus, chronic normobaric hypoxia (1) activates VEGF-A-induced angiogenesis and thereafter (2) prevents or normalizes hypertension in the SHR. Clinical Increase in blood pressure (BP) is a hallmark of anti-angiogenic treatments. We used video microscopy to measure dermal capillary densities in the dorsum of the fingers. Measurements were carried out in 18 patients before and after 6-month treatment with bevacizumab. BP was increased compared with baseline from 129 ± 13/75 ± 7 mmHg to 145 ± 17/82 ± 7 mmHg. Compared with the baseline, mean dermal capillary density was significantly lower (75 ± 12 versus 83 ± 13/mm2). Thus, bevacizumab treatment resulted in capillary rarefaction, possibly participating to the rise in BP observed in most patients. Thus, from experimental and clinical data, we might suggest that activation or blockade of angiogenesis may affect vascular resistance and, subsequently, blood pressure levels.