US appears comparable to CT in the follow-up of Talent stent grafts in our institution. The proposed simplified surveillance protocol seems safe and can lead to a significant reduction in the number of CT scans.
The microcirculation in the skin was assessed in 31 patients with sequelae from local cold injuries (LCI) in the extremities. All patients reported cold intolerance 3-4 years after the primary cold injury, which they sustained during military service. The used methods were laser Doppler fluxmetry, transcutaneous oxygen tension (TcpO2) and vital capillaroscopy. Neurovascular reflexes were stimulated by deep inspiration, digital cuff occlusion of venous and arterial circulation, neck cooling with an ice bag and water immersion at 5 and 15 °C. Unaffected lower or upper extremities were also investigated as part of a search for generalized effects of LCI. During immersion in ice water the cold-induced vasodilation (CIVD or Lewis’ ‘hunting’ reaction) was profoundly delayed or abolished in the affected limbs. These also showed the lowest skin temperatures after 15-20 min of immersion. Additionally, a delayed CIVD was found in the unaffected feet of patients with a previous hand injury. TCpO2 resting values were decreased in the patients, but oxygen reappearance time, oxygen recovery index, postocclusive reactive hyperemia and the venoarterial reflex were normal. No capillary abnormalities were found. In conclusion, LCI induces disturbances in the CIVD, impairs cold tolerance and increases the risk of future cold injuries. These data demonstrate disturbances of reflex mechanisms mediated by the central nervous system. Neurophysiologic factors seem to be more important than ischemic mechanisms in the pathophysiology of late sequelae from LCI.
The capillary blood cell velocity (CBV) was measured using two different cross-correlation systems. Cross-correlation was performed by (1) a self-tracking, analogue cross-correlation technique and (2) by a new fully computerized system. The CBV was measured at rest and during venous occlusion and post-occlusive reactive hyperemia (PRH) after 1-min arterial occlusion. The PRH response was described by determining the peak CBV. The correlations between the values obtained by the two systems were highly significant. CBV at rest: r = 0.97 (p < 0.001); CBV during venous occlusion: r = 0.97 (p < 0.001), peak CBV during PRH: r = 0.97 (p < 0.001). The stability of measurements with the computerized system was high. Only 0.08% of CBV variations was due to repeated measurements. This computerized system represents a reliable innovation which greatly facilitates CBV measurements, especially in clinical practice. The program includes automatic calculation of data (mean and maximum and minimum CBV, area under the curve, and integral, etc.).
To evaluate coronary flow reserve during cardiac catheterization, intracoronary adenosine and papaverine have been used in the clinical setting. Although papaverine maximizes coronary blood flow, it induces several toxic side effects that reduce its desirability as a coronary dilator. This investigation was designed to compare the subselective intracoronary administration of papaverine with that of adenosine in an animal model. In dogs (n = 34), we studied the effects of each agent on hemodynamics, regional myocardial blood flow, contractility (sonomicrometric and echocardiographic), metabolism (coronary arterial and venous lactate and tissue high-energy phosphates), and electrocardiographic (ST and QT intervals) parameters. Barbiturate and morphine anesthesia/analgesia was induced, and a left thoracotomy was performed. An arterial shunt was created from the left carotid artery to the left anterior descending coronary artery. Two separate groups were studied: group 1 (n = 16) for regional myocardial blood flow and mechanical function and group 2 (n = 18) for biochemical measurements. Adenosine (67 +/- 2 micrograms/min) or papaverine (6 +/- 1 mg/min) was infused into the coronary shunt at a rate of 0.5 + 0.1 ml/min for a maximum duration of 3.5 minutes. Regional myocardial blood flows were determined at control (predrug) and maximal coronary flow using radiolabeled microspheres. All hemodynamic, wall motion, biochemical, and electrocardiographic parameters were also measured at these times. Both drugs produced comparable increases in total and regional coronary blood flows (adenosine, 1.21 +/- 0.15 to 4.83 +/- 0.36 ml/min/g; papaverine, 1.21 +/- 0.05 to 4.89 +/- 0.28 ml/min/g) upon infusion into the left anterior descending coronary artery. Papaverine produced significant (p less than 0.05) changes in subendocardial ST segment electrocardiogram (-2.5 mm), QT prolongation (8 +/- 2%), myocardial creatine phosphate (47% decrease), and coronary sinus serum lactate (277% increase) compared with control. In addition, intracoronary papaverine induced an abnormal contractile pattern. No significant changes in any of these parameters (i.e., ST segment, QT prolongation, myocardial creatine phosphate level, or lactate level) were observed with intracoronary adenosine infusions. We conclude that intracoronary adenosine is comparable to papaverine for maximizing coronary blood flow without the deleterious properties observed with intracoronary papaverine.
Finger-skin microcirculation and its reactions to sympathetic stimuli were investigated in 12 patients with sympathetic dystrophies, secondary to trauma or other diseases. Nailfold-skin capillary blood cell velocity (CBV) was measured by videophotometric capillaroscopy. Laser Doppler fluxmetry was used to provide an index of skin circulation in vessels in addition to the superficial capillaries. Both CBV and laser Doppler flux (LDF) values were significantly lower in the patients, compared with the healthy controls (P less than 0.05), despite the fact that skin temperature was the same in both groups. During cooling of the contralateral hand, CBV and LDF decreased markedly (22-60%) in the control group but not in the patients (0-13%). The decrease in skin perfusion normally seen upon lowering of the hand was also impaired in the patient group (7%) compared with controls (42%) (P less than 0.05). These impaired vasomotor reflex responses are consistent with sympathetic dysfunction and may well explain some of the typical features of the syndrome, e.g. limb oedema.
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