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[Are the spontaneous coronary recanalization and the coronary collateral circulation really important in the left ventricular preservation in acute myocardial infarct?].

PURPOSE: To determine if maintenance of residual blood flow to culprit coronary artery in acute myocardial infarction is important in preserving left ventricular systolic function. METHODS: Prospective study of 63 consecutive survivors of acute myocardial infarction in the prethrombolytic era that were submitted to cinecoronary angiography and 30 degrees RAO left ventriculography on the 4th week. Culprit coronary artery patency and collateral circulation were correlated with global and segmental left ventricular contractility. RESULTS: Spontaneous coronary recanalization correlated significantly with better left ventricular systolic function only in patients with anterior wall myocardial infarction. This relationship was stronger with segmental than with global contractility. Besides, it was seen that absence of recanalization of pre-septal left anterior descending coronary artery occlusion resulted in significantly worse global and segmental left ventricular systolic function than post-septal occlusion, resulting in left ventricular aneurysm in all patients (2/3 of recanalized patients versus 1/3 of post-septal occlusions). Collateral circulation to culprit coronary artery correlated significantly with better global and segmental left ventricular contractility only in patients with inferior wall myocardial infarction. CONCLUSION: In acute anterior wall myocardial infarction spontaneous coronary artery recanalization is associated with better global and segmental left ventricular systolic function, specially if the occlusion is of pre-septal localization, while collateral circulation is not related to better contractility. In acute inferior wall myocardial infarction one sees the reverse.

Adult↗

Temporal evolution of the human coronary collateral circulation after myocardial infarction.

An analysis of the coronary collateral circulation in a consecutive series of 116 postinfarction angiograms from patients with persistent 100% occlusion of their infarct artery is reported. Patients were classified into four groups according to the interval between acute infarction and angiography. Of 42 patients studied within 6 hours of infarction (Group I), 52% had no evidence of any coronary collateral development as compared with only 8% (1 of 16 patients) studied 1 day to 2 weeks after infarction (Group II). Virtually all patients studied beyond 2 weeks after myocardial infarction (14 to 45 days, Group III) and later than 45 days (Group IV) had visible collateral flow. Angiographically "well developed" collateral channels were seen in only 16% of Group I patients compared with 62, 75 and 84% of patients in Groups II to IV, respectively. Of six patients studied twice, on the day of the infarction and 2 weeks later, only one patient had collateral vessels on the day of infarction, whereas all six patients did at follow-up study. Group I patients were studied as part of a randomized acute myocardial infarction reperfusion trial, whereas the other patients were referred for angiography primarily because of post-infarction ischemia. Within the limitations imposed by the patient selection process, it is concluded that well developed coronary collateral vessels are rarely present at the time of infarction. After infarction, they develop rapidly and are generally demonstrable within 2 weeks. It may also be inferred that the preservation of ischemic myocardium by well developed coronary collateral vessels at the time of myocardial infarction may be an uncommon occurrence.

Collateral Circulation↗

Myocardial ischemia during percutaneous transluminal coronary angioplasty in patients with rich collateral circulation of the target lesion.

Although it is commonly believed that ischemia does not develop during coronary intervention in patients with rich collateral circulation to the target vessel, ST changes are often observed, the study group comprised 40 consecutive patients who underwent elective percutaneous coronary angioplasty and who had rich collateral vessels to the target lesions. None had side branches in the target vessel that would be occluded by the angioplasty balloon. During the intervention, the 12-lead electrocardiogram was monitored for any change in the ST-T segment and 13 (32.5%) showed significant ST changes. Of these, 3 had ST changes with every balloon inflation and the remaining 10 patients had ST changes with the second or subsequent inflations. Myocardial ischemia caused by balloon inflation is not uncommon during coronary angioplasty in patients with rich collaterals to the target vessel. The collateral circulation may stop functioning very early after improvement in the forward flow of the target vessel.

Angina Pectoris↗

The extent of the collateral circulation influences the postprandial increase in portal pressure in patients with cirrhosis.

BACKGROUND: In cirrhosis, repeated flares of portal pressure and collateral blood flow provoked by postprandial hyperaemia may contribute to variceal dilation and rupture. AIM: To examine the effect of the extent of the collateral circulation on the postprandial increase in portal pressure observed in cirrhosis. PATIENTS AND METHODS: The hepatic venous pressure gradient (HVPG), hepatic blood flow and azygos blood flow were measured in 64 patients with cirrhosis before and after a standard liquid meal. RESULTS: Peak increases in HVPG (median+14.9%), hepatic blood flow (median+25.4%), and azygos blood flow (median+32.2%) occurred at 30 min after the meal. Compared with patients with marked postprandial increase in HVPG (above the median, n = 32), those showing mild (<15%, n = 32) increase in HVPG had a higher baseline azygos flow (p<0.01) and underwent a greater postprandial increase in azygos flow (p<0.02). Hepatic blood flow increased similarly in both groups. Postprandial increases in HVPG were inversely correlated (p<0.001) with both baseline azygos flow (r = -0.69) and its postprandial increase (r = -0.72). Food intake increased nitric oxide products in the azygos (p<0.01), but not in the hepatic vein. Large varices (p<0.01) and previous variceal bleeding (p<0.001) were more frequent in patients with mild increase in HVPG. CONCLUSIONS: Postprandial hyperaemia simultaneously increases HVPG and collateral flow. The extent of the collateral circulation determines the HVPG response to food intake. Patients with extensive collateralisation show less pronounced postprandial increases in HVPG, but associated with marked flares in collateral flow. Collateral vessels preserve their ability to dilate in response to increased blood flow.

Adult↗

Evaluation of brain collateral circulation by the transcranial color Doppler-guided Matas' test.

For the determination of the indication for reconstruction of the carotid artery in patients with head and neck cancer, a color Doppler-guided Matas' test was performed to examine brain collateral circulation and blood flow of the middle cerebral artery (MCA) and internal carotid artery (ICA). Both SSA-270A convex (3.75 MHz) and linear (3.75 MHz and 2.5 MHz) array probes (Toshiba Co, Ltd) were used for this investigation. A temporary occlusion test (60 seconds) by digital pressure on the common carotid artery was performed on 30 patients with head and neck cancer. The results were classified into four groups according to the relative flow volume (percent blood flow volume before the test) of the MCA: group A, with a flow volume of 87% or more; group B, with a flow volume between 72% and 86%; group C, with a flow volume between 57% and 71%; and group D, with a flow volume of 56% or less. The relative flow volume of the MCA was correlated with the ICA stump pressure and single photon emission computed tomography during a balloon Matas' test (ICA occlusion). This test seems to be useful in predicting the risk of carotid resection without reconstruction and in determining the indication for reconstruction of the carotid artery.

Adult↗

Significance of collateral circulation in reversible left ventricular asynergy by nitroglycerin in patients with relatively recent myocardial infarction.

To evaluate the functional role of coronary collateral circulation in reversible asynergy of the left ventricle, cineventriculography was performed before and after the administration of sublingual nitroglycerin in 19 patients with complete occlusion of the proximal part of the left anterior descending coronary artery. In nine patients who had significant collateral circulation to the infarct-related coronary artery (group A), there was significant improvement in both the left ventricular ejection fraction (53% to 60%, p less than 0.05) and regional wall motion in the infarct zone (8% to 18%, p less than 0.01 in the anterolateral area) with administration of nitroglycerin. In contrast, in the remaining 10 patients without significant collateral perfusion (group B), there were no detectable changes in either global function (49% versus 50%) or regional wall motion (6% versus 8% in the anterolateral area) before and after nitroglycerin. Changes in heart rate and left ventricular peak systolic and end-diastolic pressures with nitroglycerin were comparable in both groups. These results suggest that angiographically demonstrable collaterals preserve viable myocardium, which can improve its contraction when the supply-demand relationship is favorably affected because of increased collateral flow and/or more favorable loading conditions produced by nitroglycerin.

Cineradiography↗

[Chronic occlusion of a renal artery with aneurysms in the para-aortic collateral circulation and multiple aneurysms in both kidneys (author's transl)].

Chronic occlusion of the main renal artery may be followed by the development of a collateral circulation through ureteric and para-aortic arteries, and through lumbar and suprarenal arteries. A patient with occlusion of the left main renal artery is described, who developed a collateral circulation between the common iliac artery and the distal portion of the renal artery. The para-aortic collateral vessel developed one large and several small aneurysms, and there were aneurysms in both kidneys.

Aneurysm↗

Collateral circulation in hemicentral retinal vein occlusion.

The perchance occurrence of a hemicentral retinal vein occlusion in an eye with a lightly pigmented fundus allowed us the opportunity to observe the development and flow dynamics of collateral circulation. We are able to demonstrate an optic disc collateral draining into a choroidal vein, a finding which to our knowledge had previously only been documented histologically. The collateral circulation developed slowly over many months and was not rapid enough to prevent chronic microcystic macular changes.

Aged↗

Intrarenal collateral circulation in the pediatric patient.

The presence of an intrarenal collateral circulation in pediatric patients with segmental renal artery stenosis has not been stressed. Three patients demonstrating these collateral pathways are presented. The anatomy, pathogenesis, angiographic features, differential diagnosis, and significance of intrarenal collaterals in infants and children are discussed.

Adolescent↗

Development of collateral circulation in a replanted rat hindlimb model.

The development of collateral circulation was studied in a replanted rat hindlimb model by use of the hemodynamic techniques of hydrogen washout and laser Doppler capillary perfusion monitoring. Collateral development occurred and provided blood flow whose magnitude increased linearly over time. Twenty-seven percent of preligation blood flow was present at 2 weeks after replantation, 39% at 4 to 5 weeks, and 77% at 8 to 9 weeks by laser Doppler assessment. Laser Doppler correlated more closely with limb survival than did the hydrogen washout technique. Uniform necrosis (eight of eight) occurred after pedicle interruption in the 2-week group. Partial limb survival was noted in five of eight replants at 4 to 5 weeks on transection of the vascular pedicle, while complete survival of all replants (nine of nine) was seen at 8 to 9 weeks.

Animals↗

Collateral circulation in skeletal muscles: effect of pentoxifylline and torbafylline.

Vascular casts were prepared using Batson Anatomical corrosion compound, from maximally dilated rat tibialis anterior (TA), extensor digitorum longus (EDL) and soleus (SOL) with normal and limited blood supply (unilateral ligation of the common iliac artery). The weight of casts was expressed as a percentage of muscle wet weight. This value was considered representative for the size of the vascular bed. The value was 2.9 +/- 0.12% (mean +/- SEM) in normal TA, 3.37 +/- 0.15% in EDL and 4.8 +/- 0.43% in SOL. The weight of vascular casts decreased in all muscles to 40% of the values found in the contralateral muscles one week after ligation. Five weeks after ligation, it was about 60% of the control values in TA and EDL, and 80% in SOL. Treatment with torbafylline for one week did not change the weight of the vascular casts. After five weeks the size of the vascular bed was back to control values in EDL and SOL, and only 20% lower than control muscles in TA. This could be attributed to improved development of collateral circulation. Treatment with pentoxifylline improved collateral circulation only in SOL.

Animals↗

Complete interruption of the aortic arch. 2. Characteristic angiographic features with emphasis on collateral circulation to the descending aorta.

The angiocardiograms of 17 patients with aortic arch interruption are reviewed to emphasize the variations in arch interruption and origin of the brachiocephalic vessels, and collateral circulation to the descending aorta. Depending on the anatomical type and subtype of arch interruption, collateral flow to the descending aorta in the presence of a stenotic or closed ductus will be dependent on the development of intercostal collaterals and/or the presence of retrograde flow in all brachiocephalic vessels arising from the descending aorta. Familiarity with the potential pathways for collateral circulation may permit differentiation into types and subtypes on chest radiograph. Patients with Type I interruption may have bilateral rib notching if the right subclavian artery originates normally from the innominate artery, but will have rib notching confined to the left side if the origin of the right subclavian artery is aberrant. Type II or Type III interruption patients will have rib notching confined to the right side if the right subclavian has a normal origin, but no rib notching if the origin of the right subclavian artery is aberrant.

Adolescent↗

[Role of coronary collateral circulation in the compensation of disorders of myocardial perfusion and left ventricular function in patients with newly appearing angina pectoris].

The myocardial perfusion and left ventricular function were evaluated by bicycle ergometry and myocardial scintigraphy in 23 patients with primary angina taking into account the status of coronary collateral circulation in response to stenotic and occlusive atherosclerosis. In addition to severe occlusive disease of the coronary bed, most patients had significant disturbances of myocardial perfusion and left ventricular function, which were detected during exercise tests. In patients with compensatory collateral circulation in the coronary bed, such disturbances were less marked than in those without anastomoses. However collateral coronary circulation cannot be regarded to be of real value as it compensates impaired perfusion incompletely, but in some cases it can result in impaired myocardial vascularization apparently due to the steal syndrome.

Adult↗

Evaluation of cerebral collateral circulation by technetium-99m HM-PAO brain SPECT during Matas test: report of three cases.

Three cases with cerebral ischemic symptoms and an intracranial aneurysm are presented. Using [99mTc]hexamethyl-propyleneamine oxime (HM-PAO) single photon emission computed tomography imaging before and during the Matas test, a quantitative measurement method was developed for evaluating brain collateral circulation. The evaluation correlated well with findings of contrast carotid angiography. This noninvasive method seems to be useful for selection of patients for appropriate surgical treatment.

Aged↗

Damage to the collateral circulation by PTCA of an occluded coronary artery.

In this report, a patient is described with an occluded left circumflex artery, in whom the corresponding myocardium was protected at rest by sufficient collateral circulation. Because of angina pectoris class III, a PTCA of that occluded vessel was performed, complicated by a large dissection. Recruitable collateral flow, assessed from pressure calculations by a new technique, suddenly decreased at the very moment of dissection. This was accompanied by resting pain and ischemia on the ECG. This case report confirms the hypothesis that the collateral circulation can be damaged by PTCA and emphasizes that every PTCA implies a definite risk, even in case of an occluded coronary artery filled by collaterals.

Angina Pectoris↗

Vasopressin and the mature coronary collateral circulation.

In isolated vascular rings, we have shown that mature coronary collateral vessels are highly responsive to the vasoconstrictor effects of vasopressin. The purpose of the present study was to determine the effect of concentrations of vasopressin encountered in pathophysiologic states on the collateral circulation in vivo. We studied eight open-chest anesthetized dogs with mature coronary collateral vessels 3-6 months after placement of an ameroid constrictor on the left circumflex coronary artery. The left anterior descending coronary artery was perfused at constant pressure, and peripheral coronary pressure was monitored continuously throughout each experiment. At baseline and during intracoronary infusion of vasopressin, which resulted in concentrations ranging from 8 +/- 3 to 1,340 +/- 327 microM/ml, we measured regional myocardial perfusion with radiolabeled microspheres. At baseline, regional myocardial perfusion to the collateral-dependent myocardium and to the normally perfused myocardium was similar; however, during vasopressin infusion, collateral-dependent zone flow decreased by 49 +/- 14% whereas normal zone flow decreased by only 9 +/- 9% (p less than 0.0005, normal zone perfusion vs. collateral perfusion). Vasopressin increased transcollateral resistance by 242 +/- 95% above baseline but produced a more modest increase in normal zone resistance (15 +/- 10%). The subendocardial to subepicardial perfusion ratio increased by 28 +/- 12% in the normal zone in response to vasopressin but decreased by 18 +/- 11% in the collateral-dependent zone. These data show that mature coronary collateral vessels are responsive to the vasoconstrictor effects of vasopressin at concentrations encountered in various pathophysiologic states.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Occlusion of cremaster collateral circulation alters microvascular reactivity.

Surgical preparation of the rat cremaster skeletal muscle for microvascular study usually involves occlusion of the deferential artery and vein which supply a collateral circulation to the tissue. This allows removal of the testis and ductus deferens, and permits direct observation of the cremaster microvasculature. We examined with intravital microscopy the effect of this occlusion on alpha-adrenergic and nonreceptor-mediated (KCl) constriction of large arterioles (1A, 136 microns i.d.) and venules (1V, 193 microns i.d.). The acutely denervated cremaster was suspended in a tissue bath containing propranolol to block beta-adrenergic receptors. alpha 1-adrenergic (norepinephrine (NE) + rauwolscine), alpha 2-adrenergic (NE + prazosin), and KCl (+ phentolamine) concentration-response curves were obtained for bath-added agonists before vs after occlusion of the deferential circulation. Occlusion had no effect on baseline 1A diameter but increased 1V diameter slightly. Arteriolar alpha 1- and alpha 2-adrenergic sensitivities were unaffected by occlusion, but venular sensitivities were reduced by the same amount (approximately fourfold) for both receptor types. Occlusion increased arteriolar sensitivity to KCl but had no effect of venular KCl sensitivity. These data indicate that occlusion of the deferential collateral circulation can produce significant and varied effects on alpha-adrenoceptor and nonreceptor-mediated constriction of cremaster large arteriolar and venular smooth muscle, and underscore the need to avoid collateral occlusion for certain studies of the cremaster microcirculation.

Animals↗