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PubMed1976

The influence of changes in arterial CO2 and blood pressure on the collateral circulation and the regional perfusion pressure in monkeys with occlusion of the middle cerebral artery.

In 7 baboons and 5 macaques the effects of hypercapnia, hypocapnia, hypertension, and combinations of hypertension plus hypocapnia and of hypertension plus hypercapnia on the regional perfusion pressure (rPP) in the brain area rendered ischaemic by occlusion of the middle cerebral artery (MCA) were studied. A new technique for recording the pressure in the occluded MCA was used. The regional tissure pressure (rTP) was recorded with the so called wick type pressure transducers. Hypercapnia produced a marked decrease in rPP in the ischaemic brain area. Hypertension, especially in combination with hypocapnia, produced a very pronounced increase in rPP in the ischaemic brain area. The clinical implications of these findings are discussed. Occlusion of the homolateral common carotid artery (CCA) was followed by a very slight and transient drop in the occluded MCA pressure. Occlusion of the occluded MCA pressure.

Animals↗
PubMed1975

The influence of changes in arterial CO2 and blood pressure on the collateral circulation and the regional perfusion pressure in monkeys with occlusion of the middle cerebral artery.

In 7 baboons and 5 macaques the effects of hypercapnia, hypocapnia, hypertension, and combinations of hypertension plus hypocapnia and of hypertension plus hypercapnia on the regional perfusion pressure (rPP) in the brain area rendered ischaemic by occlusion of the middle cerebral artery (MCA) were studied. A new technique for recording the pressure in the occluded MCA was used. The regional tissue pressure (rTP) was recorded with the so called wick type pressure transducers. Hypercapnia produced a marked decrease in rPP in the ischaemic brain area. Hypertension, especially in combination with hypocapnia, produced a very pronounced increase in rPP in the ischaemic brain area. The clinical implications of these findings are discussed. Occlusion of the homolateral common carotid artery (CCA) was followed by a very slight and transient drop in the occluded MCA pressure. Occlusion of the contralateral CCA was followed by a marked and persistent drop in the occluded MCA pressure.

Animals↗
PubMed1977

[Development of collateral circulation following an experimental gunshot wound to the shoulder].

Peculiarities in the development of collateral blood circulation and skin temperature of the foreleg were studied in two series of experiments (38 dogs) after gunshot wound of the humeral area, lesion of vessel-nervous bundle (first series) and humeral artery resection with section of medial and ulnar nerves (second series). In animals of the first series, the blood circulation was states to restore within a month at the expense of the arteries of the posterior humeral muscles, mainly. Further circulatroy improvement develops due to anastomoses in the anterior humeral muscles, as well as some intrasystemic roundabout ways in humeral area and shoulder girdle. Three months later, the humeral vessels network increases, it does not prevent, however, trophic ulceration of the ulnar skin. Skin temperature of the distal extremital parts raised to normal by 19--20 day of the experiment. The animals from the second series demonstrated retarded development of the roundabout ways in the operated extremities during the whole follow-up period (180 days). Skin temperature was lowered during the first 3--4 days, gradually reached the temperature of the contralateral extremity.

Animals↗
PubMed1984

Evaluation of coronary collateral circulation in conscious humans.

The physiologic importance of coronary collateral vessels was investigated in 19 men undergoing transient proximal occlusion of the left anterior descending (LAD) branch without sedative medication. No vasodilators were given before LAD balloon occlusion. Six men had angiographic filling of the LAD via coronary collateral vessels (Group 1) and 13 did not (Group 2). Aortic, distal coronary and left ventricular (LV) filling pressures and great cardiac vein blood flow (thermodilution) were recorded continuously during occlusion. During LAD occlusion, clinical and electrocardiographic evidence for transient myocardial ischemia occurred more often in patients in Group 2 than in Group 1, but the difference was not statistically significant. Heart rate and aortic and distal coronary pressures were similar in Groups 1 and 2. LV filling pressure was 3 mm Hg higher in Group 2 patients (p less than 0.05). The aortic to distal coronary pressure difference and the distal coronary to LV filling pressure difference were also similar in Groups 1 and 2. However, residual great cardiac vein flow was 55% higher (p less than 0.05) and the calculated coronary collateral resistance index was 45% lower in patients in Group 2 compared with those in Group 1 (p less than 0.01). Coupling of regional coronary venous blood flow estimates to pressure measurements routinely made during angioplasty is a new technique that allows evaluation of determinants of coronary collateral function in conscious humans.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Disuse inhibition of newly functional coronary collateral circulation in ponies.

We evaluated the loss of coronary collateral function in the absence of stimulation (disuse inhibition) by doubling the interval between successive left anterior descending coronary artery (LAD) occlusions in ponies in which collateral function initially had been enhanced by 2-min occlusions at 30-min intervals. Before collateralization, occlusion caused segment systolic shortening, velocity of shortening, and stroke work index in the LAD-dependent left ventricular apex to decrease, whereas heart rate and left ventricular end-diastolic pressure increased. After 476 +/- 102 occlusions, segment function recovered to preocclusion levels and hemodynamics were unchanged during occlusion. Occlusion did not elicit sustained functional deterioration until the occlusion interval was greater than or equal to 32 h. During the occlusion after the 128-h interval, segment systolic shortening, velocity of shortening, and stroke work index were reduced 69 +/- 8, 38 +/- 9, and 46 +/- 13%, respectively. Percent recovery of systolic shortening during successive occlusions declined exponentially (T1/e = 102.0 +/- 17.3 h). Thus, in ponies collateral function progressively declines when the occlusion interval is greater than or equal to 32 h, but complete inhibition does not occur even after 128 h without occlusion. This indicates that collateral function in ponies can be maintained by occlusions that are far less frequent than those needed for initial collateral development. The long time constant of collateral disuse inhibition suggests that equine collaterals are quite resistant to the effects of occlusion cessation and differ from canine collaterals in that respect.

Animals↗
PubMed1980

Surgical treatment of coarctation of the aorta with minimal collateral circulation.

Twenty-four aortic coarctation patients with minimal collaterals were operated on. Left-side bypass was used in 18 cases, internal shunt in 4, while a jump graft ws inserted in 2 cases. These methods were applied when the distal aortic pressure fell below 50 mmHg systolic during test clamping. The coarctation was corrected with isthmusplasty in 12 cases, resection and end-to-end anastomosis in 5 cases, resection with prosthetic replacement in 5 cases and jump graft in 2 cases. The operative mortality was 2 patients (8.3%). One patient died of complications of a post-perfusion bleeding tendency; the other, who had concomitant aortic insufficiency, died of cerebral infarction and pneumonia. At follow-up examination, the blood pressure difference between the upper and lower extremities had disappeared in all cases. The blood pressure was still over 150 mmHg systolic in 9 patients, 8 of whom received anti-hypertensive medication. One patient died during the follow-up period, while waiting for an operation for aortic insufficiency.

Adolescent↗
PubMed1971

Clinico-radiological study of collateral circulation after internal carotid and middle cerebral occlusion.

The intracranial collateral channels apart from the circle of Willis have been studied angiographically in 34 patients with internal carotid artery occlusion and 19 with occlusion of the middle cerebral artery. These collaterals are present in a high percentage of cases within a week of the ictus and are more common when the stroke has developed slowly. Their presence in occlusion of the middle cerebral artery seems to offer some protection against infarction but in internal carotid artery occlusion they are less important than the circle of Willis and when present suggest inadequacy of this structure.

Adult↗
PubMed1976

[Plasticity of blood vessels of the heart and lungs in collateral circulation under conditions of high altitude].

The combination of the collateral blood flow in the heart and lungs with effects of Alpine hypoxia and pronounced additional loads was found to allow the detecting of plastical capacities of these organs in a sufficiently full volume. The experiments were performed in 273 dogs by microscopic, macro-microscopic, macroscopic and partly functional methods. The collateral coronary blood flow (after ligation of the anterior interventricular artery) under Alpine conditions (3200 m over the sea level) combined with compensatory hyperfunction of the heart (due to stenosing of the aorta arc), gets worse as compared with the conditions of the valley. In these experiments in mountains the extra- and intraorganic anastomoses are more pronounced, the capacity of the coronary artery branches being less pronounced than in the valley. The muscle fibres grow thicker, the heart weight enlarges, the diffusion distances of capillaries increase and the ratio of the arterial bed capacity and the heart weight decreases. Under Alphine conditions (as compared with the valley) the collateral blood flow of lungs deteriorates (after ligation of two lobar branches of the pulmonary artery or of the lobar vein) against the background of additional loads (stenosing of the aorta arc or pulmonectomy). Deterioration of the collateral bloodflow is related with the combination of conditions of the alphine hypoxia with additional loads resulting in a weakening or even block of compensatory reactions of pulmonary or bronchial arteries and veins.

Altitude Sickness↗