scholarly journals The significance of coronary collateral circulation in the preservation of myocardial function

2007 ◽  
Vol 60 (5-6) ◽  
pp. 287-291
Author(s):  
Vladimir Ivanovic ◽  
Nikola Jelkic ◽  
Miroslav Bikicki ◽  
Milovan Petrovic ◽  
Tibor Canji ◽  
...  
Keyword(s):  
Coronary Artery ◽  
Blood Vessels ◽  
Collateral Circulation ◽  
Stress Test ◽  
Coronary Artery Occlusion ◽  
Artery Occlusion ◽  
Left Ventricular ◽  
Vessel Occlusion ◽  
Total Occlusion ◽  
Coronary Stent Implantation

Introduction: After occlusion or subocclusion of the blood vessels, myocardial perfusion is maintained through the collateral vessels. There are two mechanisms of vessel formation: arteriogenesis and angiogenesis. The term arteriogenesis describes the growth of the existing collaterals into mature arteries. On the other hand, angiogenesis, is a process of developing new blood vessels from the preexisting ones. Collateral blood vessels have many functional roles. If they are adequately developed, they can protect the myocardium from ischemic injury. Even when a total occlusion develops, regional left ventricular motility is better in segments with developed collateral circulation. In patients with well-developed collaterals, who experience coronary artery occlusion, often there is no evidence of myocardial infarction in the area of the occluded artery. Well-developed collaterals reduce the risk of unstable cardiac events. Case report A case of right coronary artery occlusion with good collateral circulation and preserved myocardial left ventricular motility is presented. After coronary stent implantation, the patient was asymptomatic, and the maximal stress test for myocardial ischemia was negative. Conclusion: Despite coronary vessel occlusion, collateral blood flow maintains the pump function of the left ventricle.

Coronary artery embolization in closed-chest canines using flexible radiopaque plugs

1988 ◽  
Vol 64 (5) ◽  
pp. 2236-2239 ◽  
Author(s):  
M. D. Herr ◽  
J. J. McInerney ◽  
G. L. Copenhaver ◽  
D. L. Morris
Keyword(s):  
Coronary Artery ◽  
Coronary Artery Occlusion ◽  
Artery Occlusion ◽  
Left Ventricular ◽  
Vessel Occlusion ◽  
Closed Chest ◽  
Anesthetized Dogs ◽  
Dental Impression ◽  
The Mean ◽  
A New Technique

A new technique induces localized myocardial infarction in closed-chest dogs by placing discrete plugs in coronary arteries without using cumbersome coaxial catheters or guide wires. Flexible plugs, essential to this method, are formed by extruding a dental impression polymer, rendered radiopaque with sodium iodide, into spaghetti-like strands. Segments of these strands can be injected through a catheter into a selected coronary artery. Contact with blood or saline causes plugs to swell. The mean increase in plug diameter due to swelling was 27 +/- 20%. Eight anesthetized dogs were embolized via carotid approach [6 left anterior descending (LAD), 1 left circumflex (LCX), and 1 LAD and LCX]. Plug positions were monitored fluoroscopically. One animal died at 2 days postembolization. The remaining seven dogs were killed after 14–37 days. Autopsies showed complete vessel occlusion and localized infarction. Infarcts resulting from coronary artery occlusion with one, two, or three plugs involved 2–26% of the left ventricular mass.

Early time course of myocardial electrical impedance during acute coronary artery occlusion in pigs, dogs, and humans

2005 ◽  
Vol 99 (4) ◽  
pp. 1576-1581 ◽  
Author(s):  
Carlos L. del Rio ◽  
Patrick I. McConnell ◽  
Bradley D. Clymer ◽  
Roger Dzwonczyk ◽  
Robert E. Michler ◽  
...  
Keyword(s):  
Coronary Artery ◽  
Time Course ◽  
Electrical Impedance ◽  
Early Time ◽  
Coronary Artery Occlusion ◽  
Artery Occlusion ◽  
Acute Ischemia ◽  
Collateral Flow ◽  
Total Occlusion ◽  
Interspecies Differences

Changes in myocardial electrical impedance (MEI) and physiological end points have been correlated during acute ischemia. However, the importance of MEI's early time course is not clear. This study evaluates such significance, by comparing the temporal behavior of MEI during acute total occlusion of the left anterior descending coronary artery in anesthetized humans, dogs, and pigs. Here, interspecies differences in three MEI parameters (baseline, time to plateau onset, and plateau value normalized by baseline) were evaluated using Kruskal-Wallis ANOVA and post hoc tests ( P < 0.05). Noteworthy differences in the MEI time to plateau onset were observed: In dogs, MEI ischemic plateau was reached after 46.3 min (SD 12.9) min of occlusion, a significantly longer period compared with that of pigs and humans [4.7 (SD 1.2) and 4.1 min (SD 1.9), respectively]. However, no differences could be observed between both animal species regarding the normalized MEI ischemic plateau value (15.3% (SD 4.7) in pigs, vs. 19.6% (SD 2.6) in dogs). For all studied MEI parameters, only swine values resembled those of humans. The severity of myocardial supply ischemia, resulting from coronary artery occlusion, is known to be dependent on collateral flow. Thus, because dogs possess a well-developed collateral system (unlike humans or pigs), they have shown superior resistance to occlusion of a coronary artery. Here, the early MEI time course after left anterior descending coronary artery occlusion, represented by the time required to reach ischemic plateau, was proven to reflect such interspecies differences.

scholarly journals The retrograde technique for recanalization of chronically occluded coronary arteries: Case series report

2020 ◽  
pp. 124-124
Author(s):  
Stefan Juricic ◽  
Milorad Tesic ◽  
Milan Dobric ◽  
Srdjan Aleksandric ◽  
Zlatko Mehmedbegovic ◽  
...  
Keyword(s):  
Coronary Artery ◽  
Case Series ◽  
Interventional Cardiology ◽  
Coronary Artery Occlusion ◽  
Artery Occlusion ◽  
Special Technique ◽  
Retrograde Approach ◽  
Total Occlusion ◽  
Antegrade Approach ◽  
Increased Risk

Background. Chronic total occlusion (CTO) of coronary artery still represents one of the most challenging lesion subset in field of interventional cardiology. Considering the complexity and increased risk posed by the retrograde approach, it is most often performed after a failed antegrade approach. Methods. We present a series of cases dedicated to the retrograde approach as a special technique for the treatment of chronic total coronary artery occlusion. All cases have some special characteristics that are today part of a dedicated portfolio in every cath lab. Results. In our series of cases all of three percutaneous coronary interventions (PCI) with retrograde approach finished with successful recanalization of CTO with different strategy and supported with rotational atherectomy (RA) or intravascular ultrasound (IVUS). Conclusion. In cases where there is the presence of interventional collaterals, as well as when the anterograde approach is very difficult, the retrograde approach can increase the success rate of procedures. The retrograde approach requires a long learning curve as well as very skilled and experienced operators who are able to perform the procedure independently.

scholarly journals A Sign to Heaven: aVR Lead Elevation and Myocardial Infarction

2011 ◽  
Vol 11 ◽  
pp. 662-665
Author(s):  
Amir M. Nia ◽  
Natig Gassanov ◽  
Hannes Reuter ◽  
Fikret Er
Keyword(s):  
Myocardial Infarction ◽  
Coronary Artery ◽  
Proximal Part ◽  
Coronary Artery Occlusion ◽  
Artery Occlusion ◽  
Correct Treatment ◽  
Total Occlusion ◽  
St Segment Elevation ◽  
St Segment ◽  
Long Time

Isolated ST-segment elevation only in the aVR lead, reflecting an acute myocardial infarction due to a left main coronary artery occlusion, was ignored as part of physicians' training in emergency medicine for a long time. The recognition of aVR lead elevation is becoming more accepted as a mandatory diagnostic tool, in particular for physicians working at emergency departments. We report a typical myocardial infarction with total occlusion of the proximal part of the left anterior coronary artery, presenting with ST-segment elevation in the aVR lead, which was misinterpreted as diffuse ischemia. The lacking mandatory awareness of this entity endangered prompt and correct treatment.

Effect of exercise on coronary pressure-flow relationship in hypertrophied left ventricle

1995 ◽  
Vol 269 (1) ◽  
pp. H271-H281 ◽  
Author(s):  
D. J. Duncker ◽  
J. Zhang ◽  
T. J. Pavek ◽  
M. J. Crampton ◽  
R. J. Bache
Keyword(s):  
Coronary Artery ◽  
Myocardial Perfusion ◽  
Diastolic Pressure ◽  
Coronary Artery Occlusion ◽  
Artery Occlusion ◽  
Left Ventricular ◽  
Back Pressure ◽  
Pressure Flow ◽  
Pronounced Increase ◽  
Coronary Pressure

Left ventricular (LV) hypertrophy (LVH) secondary to chronic pressure overload is associated with increased susceptibility to myocardial hypoperfusion and ischemia during exercise. The present study was performed to determine whether exercise causes alterations in minimum coronary resistance or effective back pressure [coronary pressure at zero flow (Pzf)] that limit maximum myocardial perfusion in the hypertrophied heart. Ascending aortic banding in 7 dogs increased the LV weight-to-body weight ratio to 7.7 +/- 0.3 g/kg compared with 4.6 +/- 0.2 g/kg in 11 normal dogs (P < 0.01). Maximum coronary vasodilation was produced by intracoronary infusion of adenosine. Under resting conditions, the slope of the pressure-flow relationship (conductance) was significantly lower in the LVH animals than in the normal dogs (7.2 +/- 0.8 vs. 11.9 +/- 0.8 x 10(-2) ml.min-1.g-1.mmHg-1; P < 0.01); the slope correlated with the degree of hypertrophy r = 0.74; P < 0.001). The Pzf measured during total coronary artery occlusion (Pzf,measured) was significantly elevated in LVH compared with normal dogs (25.6 +/- 2.2 vs. 13.0 +/- 1.2 mmHg; P < 0.01); Pzf,measured was positively correlated (r = 0.78, P < 0.0005) with LV end-diastolic pressure measured during total coronary artery occlusion (9.0 +/- 1.1 mmHg in normal dogs and 22.2 +/- 3.2 mmHg in LVH dogs; P < 0.01). Graded treadmill exercise to maximum heart rates of 210 +/- 9 and 201 +/- 8 beats/min in normal and LVH animals, respectively, caused similar decreases in the slope of the pressure-flow relationship in LVH (from 7.7 +/- 0.9 to 6.1 +/- 0.8 x 10(-2) ml.min-1.g-1.mmHg-1; P < 0.01) and normal dogs (from 11.9 +/- 0.8 to 10.0 +/- 0.7 x 10(-2) ml.min-1.g-1.mmHg-1; P < 0.01). However, exercise-induced increases in Pzf,measured were significantly greater in the LVH animals (from 25.6 +/- 2.2 to 40.8 +/- 2.1 mmHg; P < 0.01) than in normal animals (from 13.0 +/- 1.2 to 24 +/- 2.1 mmHg; P < 0.01) (P < 0.01 LVH vs. normal). The greater increase in Pzf paralleled a more pronounced increase in LV end-diastolic pressure in the LVH dogs from 22.2 +/- 3.2 to 39.1 +/- 2.7 mmHg) than in normal dogs from 9.0 +/- 1.1 to 14.2 +/- 2.0 mmHg). The results suggest that exaggerated increases in filling pressure during exercise in the hypertrophied left ventricles contributed to impairment of myocardial perfusion during exercise by augmenting the back pressure, which opposes coronary flow.(ABSTRACT TRUNCATED AT 400 WORDS)

Long-Term Effects of Growth Hormone on Infarct Size and Left Ventricular Function in Sheep With Coronary Artery Occlusion

2010 ◽  
Vol 55 (3) ◽  
pp. 255-261
Author(s):  
Fernanda D Olea ◽  
Andrea De Lorenzi ◽  
Claudia Cortés ◽  
Patricia Cabeza Meckert ◽  
Oscar Cendoya ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Coronary Artery ◽  
Left Ventricular Function ◽  
Infarct Size ◽  
Ventricular Function ◽  
Coronary Artery Occlusion ◽  
Artery Occlusion ◽  
Left Ventricular ◽  
Long Term Effects
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