Clinical Signs Of Ischemia Research Articles

ERRATUM TO: Myocardial Injury Among Postoperative Patients: Where Is the Wisdom in Our Knowledge?

The author would like to make the following correction to the Editorial, originally published in the July issue of the Journal of Hospital Medicine 2020;15(7):447-448. DOI 10.12788/jhm.3468. In the third paragraph, MINS was described as an “umbrella term that can indicate either a myocardial infarction (MI) or nonischemic myocardial injury (NIMI).” This is not fully accurate: MINS is an umbrella term that can indicate either an MI or other myocardial injury due to ischemia. The correction to the paragraph is as follows, indicated in bold type: In this journal issue, Cohn and colleagues summarize the current information around this phenomenon of myocardial injury after noncardiac surgery, or MINS.1 Consistent with the literature, they define MINS as an acute rise and/or fall in troponin (above the assay's upper limit of normal) at any point in the 30 days following noncardiac surgery. Importantly, MINS is an umbrella term that can indicate either an MI or other myocardial injury due to ischemia. An MI exists if there are clinical signs of ischemia and/or objective evidence of infarction on imaging.

Detection of severe digital vasculopathy in systemic sclerosis by colour Doppler sonography is associated with digital ulcers.

Colour Doppler ultrasonography (CDUS) is very important in general vascular diagnostic procedures. Its role in determining the extent of vasculopathy in Systemic Sclerosis (SSc) needs further investigation. The aim of this study was to compare the presence of altered arteries with nailfold capillaroscopy and clinical signs of ischaemia, that is, digital ulcers or pitting scars (DU/PS). A feasible CDUS protocol is provided. Two thousand five hundred and twenty-eight arteries of the fingers, palms and wrists from 79 SSc patients (32 arteries per patient) were examined using CDUS. Furthermore, nailfold capillaroscopy, clinical and laboratory data were evaluated. Narrowed or occluded lumens were seen in 39.8% of all assessable arteries (n = 2489) and 48.9% of all proper palmar digital arteries (n = 1564) but only 15.6% (P < 0.0001) of proximal arteries (n = 924). Fingerwise analyses presented significant coincidence of pathological CDUS findings and DU/PS (P = 0.0009). Pathological CDUS findings were also associated with elevated CRP concentrations, current or past smoking with ⩾20 pack-years, male gender and present or past DU/PS. Receiver operating characteristic curve analysis (area under the curve = 0.727) suggested a cut-off value of ⩾20% pathological vessels (sensitivity: 90.7%; specificity: 47.8%) for the presence of DU/PS. An examination protocol focusing on the right-hand digits II-V (proper palmar digital arteries) revealed similar results (area under the curve = 0.751; sensitivity: 93.0%; specificity: 43.5%). CDUS of hand and finger arteries allows measurement of the extent of SSc vasculopathy, which is associated with clinical signs of chronic malperfusion. A shortened examination protocol of CDUS (right-hand digits II-V; 15 min instead of 45 min examination time) could complement vascular diagnostics in SSc.

Evaluación funcional de la revascularización con arteria mamaria sobre la descendente anterior mediante el estudio de la reserva coronaria con ecocardiografía transtorácica

Transthoracic echocardiography allows the coronary flow reserve to be determined non-invasively, and is a useful method to evaluate the functional results of coronary circulation after revascularization. The aim of this study was to analyse the different factors that affect the coronary flow reserve after revascularization of the descending anterior coronary artery with the left internal mammary artery. Material and methodsThe coronary flow reserve was studied three months after surgery using transthoracic echocardiography. The study included 43 patients with no clinical signs of ischemia in the anterior wall after coronary artery bypass graft surgery with left internal mammary artery. A control group of 50 cases with similar cardiovascular risks, but without ischemic cardiomyopathy was also studied. ResultsAlthough both groups showed low coronary flow reserve, patients that underwent surgery had a lower result (2.00 (SD 0.52)) than control patients with cardiovascular risk factors (2.93 (SD 0,80)), P<.001. A multivariate analysis showed that coronary flow reserve is lower when severity of the lesion is smaller 2.66E-02 (0.003-0.05), P=.028 and also when the quality of the distal vessel is worse 0.361 (0.070-0.651), P=.016. ConclusionsCoronary flow reserve after revascularization is lower than in control patients with similar cardiovascular risk factors. Revascularization of cases in which severity of the lesion is not too important determines a low coronary flow reserve in the anterior descending coronary artery, which is even worse if the distal vessel is of a low conduit. Transthoracic echocardiography allows the the revascularization of the descending anterior coronary artery with left internal mammary artery to be functionally evaluated.

A case of popliteal artery aneurysm associated with popliteal artery entrapment syndrome.

Popliteal artery entrapment (PAE) is an uncommon syndrome. Although this phenomenon can cause claudication in younger populations, other clinical features may vary. The present report describes a case of a 48-year-old woman who was referred for treatment of a pulsatile mass in the right popliteal fossa. Computed tomography scan and magnetic resonance imaging demonstrated popliteal aneurysm associated with PAE. Resection of abnormal musculotendinous structures, aneurysmectomy and subsequent revascularization were successfully performed. Although PAE may lead to poststenotic dilatation and aneurysm formation, huge aneurysm without clinical signs of ischemia in a patient with PAE is extremely rare.Popliteal artery entrapment (PAE) is an uncommon syndrome. Although this phenomenon can cause claudication in younger populations, other clinical features may vary. The present report describes a case of a 48-year-old woman who was referred for treatment of a pulsatile mass in the right popliteal fossa. Computed tomography scan and magnetic resonance imaging demonstrated popliteal aneurysm associated with PAE. Resection of abnormal musculotendinous structures, aneurysmectomy and subsequent revascularization were successfully performed. Although PAE may lead to poststenotic dilatation and aneurysm formation, huge aneurysm without clinical signs of ischemia in a patient with PAE is extremely rare.

A Case of Popliteal Artery Aneurysm Associated with Popliteal Artery Entrapment Syndrome

Popliteal artery entrapment (PAE) is an uncommon syndrome. Although this phenomenon can cause claudication in younger populations, other clinical features may vary. The present report describes a case of a 48-year-old woman who was referred for treatment of a pulsatile mass in the right popliteal fossa. Computed tomography scan and magnetic resonance imaging demonstrated popliteal aneurysm associated with PAE. Resection of abnormal musculotendinous structures, aneurysmectomy and subsequent revascularization were successfully performed. Although PAE may lead to poststenotic dilatation and aneurysm formation, huge aneurysm without clinical signs of ischemia in a patient with PAE is extremely rare.

Practical Management of Knee Dislocations: A Selective Angiography Protocol to Detect Limb-Threatening Vascular Injuries

Knee dislocations are relatively uncommon but potentially catastrophic injuries. In athletes, these injuries generally result from high-energy traumatic mechanisms such as collisions in football and rugby, high-velocity falls in skiing, and falls from heights in gymnastics and extreme sports. Knee dislocations are frequently associated with coincident neurological or vascular injuries. Recognition of vascular injury is particularly challenging because vascular compromise may not be immediately associated with clinical signs of ischemia and may result from injuries without complete or evident dislocation. This article reviews the rationale behind selective angiography, adjunctive vascular testing, and the need for observation after multiligament knee trauma. An algorithm for the diagnosis of vascular injuries is presented.

A multi-centre randomised controlled trial of minimally invasive direct coronary bypass grafting versus percutaneous transluminal coronary angioplasty with stenting for proximal stenosis of the left anterior descending coronary artery

To compare the clinical- and cost-effectiveness of minimally invasive direct coronary artery bypass grafting (MIDCAB) and percutaneous transluminal coronary angioplasty (PTCA) with or without stenting in patients with single-vessel disease of the left anterior descending coronary artery (LAD). Multi-centre randomised trial without blinding. The computer-generated sequence of randomised assignments was stratified by centre, allocated participants in blocks and was concealed using a centralised telephone facility. Four tertiary cardiothoracic surgery centres in England. Patients with ischaemic heart disease with at least 50% proximal stenosis of the LAD, suitable for either PTCA or MIDCAB, and with no significant disease in another vessel. Patients randomised to PTCA had local anaesthetic and underwent PTCA according to the method preferred by the operator carrying out the procedure. Patients randomised to MIDCAB had general anaesthetic. The chest was opened through an 8-10-cm left anterior thoracotomy. The ribs were retracted and the left internal thoracic artery (LITA) harvested. The pericardium was opened in the line of the LAD to confirm the feasibility of operation. The distal LITA was anastomosed end-to-side to an arteriotomy in the LAD. All operators were experienced in carrying out MIDCAB. The primary outcome measure was survival free from cardiac-related events. Relevant events were death, myocardial infarction, repeat coronary revascularisation and recurrence of symptomatic angina or clinical signs of ischaemia during an exercise tolerance test at annual follow-up. Secondary outcome measures were complications, functional outcome, disease-specific and generic quality of life, health and social services resource use and their costs. A total of 12,828 consecutive patients undergoing an angiogram were logged at participating centres from November 1999 to December 2001. Of the 1091 patients with proximal stenosis of the LAD, 127 were eligible and consented to take part; 100 were randomised and the remaining 27 consented to follow-up. All randomised participants were included in an intention-to-treat analysis of survival free from cardiac-related events, which found a non-significant benefit from MIDCAB. Cumulative hazard rates at 12 months were estimated to be 7.1 and 9.2% for MIDCAB and PTCA, respectively. There were no important differences between MIDCAB and PTCA with respect to angina symptoms or disease-specific or generic quality of life. The total NHS procedure costs were 1648 British pounds and 946 British pounds for MIDCAB and PTCA, respectively. The costs of resources used during 1 year of follow-up were 1033 British pounds and 843 British pounds, respectively. The study found no evidence that MIDCAB was more effective than PTCA. The procedure costs of MIDCAB were observed to be considerably higher than those of PTCA. Given these findings, it is unlikely that MIDCAB represents a cost-effective use of resources in the reference population. Recent advances in cardiac surgery mean that surgeons now tend to carry out off-pump bypass grafting via a sternotomy instead of MIDCAB. At the same time, cardiologists are treating more patients with multi-vessel disease by PTCA. Future primary research should focus on this comparison. Other small trials of PTCA versus MIDCAB have now finished and a more conclusive answer to the original objective could be provided by a systematic review.

Myocardial energy metabolism during ischemia and the mechanisms of metabolic therapies.

The primary effect of ischemia is reduced aerobic adenosine triphosphate (ATP) formation in mitochondria. This triggers accelerated glycolysis and reduced cell pH, Ca(2+) accumulation, K(+) efflux, adenosine formation, and the clinical signs of ischemia: chest pain and a shift in the ST segment. Traditional therapies for angina are aimed at either decreasing the need for ATP by suppressing heart rate, blood pressure, and cardiac contractility, or at increasing oxygen delivery to the mitochondria, or both. An additional approach to treating angina is to suppress myocardial fatty acid oxidation, increase pyruvate oxidation, and reduce anaerobic glycolysis. High fatty acid levels result in oxygen wasting and inhibit the oxidation of pyruvate in the mitochondria. In experimental models, the partial inhibition of myocardial fatty acid oxidation with agents such as oxfenicine, ranolazine, and trimetazidine stimulates glucose oxidation and reduces lactate production during ischemia. Clinical studies demonstrate that this approach is as effective as traditional hemodynamic therapies at improving exercise tolerance and reducing the frequency of angina. Moreover, because these agents do not suppress heart rate, blood pressure, or contractility, they are effective as add-on therapy to Ca(2+)-channel and beta-adrenergic receptor antagonists.

Frequent embolization in peripheral angioplasty: detection with an embolism protection device (AngioGuard) and electron microscopy.

To evaluate the deliverability and protection capabilities of an embolism protection filter in angioplasty of peripheral arteries. The Angioguard emboli capture guidewire system was applied in 11 patients with femoropopliteal lesions (6 stenoses, 3 occlusions, 2 controls). Data on lesion crossing, flow deceleration and macroembolization were recorded. Filter membranes were evaluated with scanning electron microscopy (SEM). System delivery was successful in all patients. Primary lesion crossing was feasible in four of six stenoses; predilatation was required in two of six. Marked flow deceleration was recorded in six patients. Emboli next to the filter were detected in each patient with concentric plaques, but could not reliably be removed with the filter. Downstream macroembolization was also present in all patients with concentric stenoses, but in none with chronic occlusion. None of the patients had clinical signs of ischemia. SEM analysis demonstrated only small particles on control group filters and non-obliterating fibrinous conglomerates on filters used in chronic occlusion. Substantial obliteration was seen on several filters used in stenotic lesions. Microembolization of fibrin aggregates is a common incident in balloon angioplasty of femoropopliteal stenoses. Macroembolization occurred more frequently than previously reported. The use of embolism protection filters aided in the detection but not in the removal of larger emboli.

Early outcome and graft patency in mammary artery grafting of left anterior descending artery with sternotomy or anterior minithoracotomy

Background. The main objective of this study was to retrospectively compare early outcome and graft patency in patients who underwent coronary artery bypass grafting with the internal thoracic artery to the left anterior descending artery via an anterior minithoracotomy or median sternotomy and without the use of extracorporeal circulation. Methods. One hundred thirty consecutive patients were studied. Median sternotomy was performed in 77 patients and anterior minithoracotomy in 53 patients. Results. There were no differences in early clinical data or persistent postoperative pain between the groups. Early graft patency was 88% in the thoracotomy group and 96% in the sternotomy group ( p = 0.3). Five of 7 patients who presented with a significant stenosis at the first coronary angiography had a normal angiogram at the reangiography. None of the patients with nonsignificant stenosis at the early coronary angiography had any clinical signs of ischemia or chest pain. Conclusions. In our experience, anterior minithoracotomy and median sternotomy are different and distinguishable regarding early outcome and early graft patency. Most of the stenoses visualized at the early coronary angiography had vanished at a later coronary angiography, which makes the interpretation of the angiogram hazardous as a tool for the decision for redo procedure in the early postoperative period.

A double bifurcated graft for abdominal aorta and bilateral iliac artery reconstruction.

Revascularization of the hypogastric artery often tends to be neglected in aortoiliac reconstructive surgery; however, its incomplete revascularization can result in unfavorable complications such as buttock claudication or necrosis, vascular impotence, and colonic ischemia. Multiple vascular lesions in the abdominal aorta and bilateral iliac arteries were reconstructed using a newly designed double bifurcated graft in five male patients. All five patients demonstrated excellent graft limb patency and postoperative improvement of the ankle-brachial pressure index without any clinical signs of ischemia in regions of the hypogastric artery. Thus, we conclude that an aggressive approach toward hypogastric circulation maintenance is essential in aortoiliac reconstructive surgery. By using this double bifurcated graft, rapid and safe revascularization of the bilateral hypogastric arteries concomitant with the external iliac or femoral arteries can be performed.

Superselective Coil Embolization in Acute Gastrointestinal Hemorrhage: Personal Experience in 10 Patients and Review of the Literature

To evaluate the safety and efficiency of microcoil embolization in upper and lower gastrointestinal hemorrhage. Superselective microcoil embolization was performed in 10 patients (upper gastrointestinal bleeding, n = 3; lower gastrointestinal bleeding, n = 7) who had acute gastrointestinal hemorrhage. Embolization was performed as peripherally as possible with use of coaxial catheter systems. Embolization materials included microcoils (2-4 mm) alone (n = 5), microcoils and polyvinyl alcohol particles (355-500 microm) (n = 4), and microcoils and gelatin sponge particles (n = 1). Immediate hemostasis was achieved in eight patients. In two patients with dual blood supply of the bleeding site, significant reduction of hemorrhage resulted. In these two patients, it was technically impossible to place the coaxial catheter distally enough to allow safe embolization of both feeding vessels. No clinical signs of ischemia or infarction were observed after intervention. Microcoil embolization is a safe and efficient procedure for controlling acute lower gastrointestinal bleeding if performed in a superselective catheter position. In upper gastrointestinal bleeding, microcoil embolization is an established treatment and can be performed more proximally.

SCINTIGRAPHIC ASSESSMENT OF DISTAL EXTREMITY PERFUSION IN 17 PATIENTS

To assess the role of scintigraphic evaluation of distal limb perfusion, the medical records and scintigraphic perfusion images of 17 animals (8 dogs, 2 cats, 2 calves, 4 birds and 1 ferret) with clinical signs of distal limb ischemia were examined retrospectively. Images were obtained at 5 and 10 minutes following injection of 99mTc-MDP, or 99mTc-DTPA. The initial scintigraphic diagnoses of 17 animals included complete ischemia (8/17), partially reduced perfusion (5/17), and normal to increased perfusion (4/17). In 4 of the animals with partially reduced perfusion, follow-up scans indicated progression to complete ischemia (1/4) or normal to increased perfusion (3/4). Nine of 17 animals had a final scintigraphic diagnosis of complete distal limb ischemia, and these animals were either euthanized (5/9) or had limb amputation (4/9). A final diagnosis of complete ischemia was supported with either repeat scanning (3/10), continued clinical observation (6/10) and/or pathological examination (10/10). Clinical signs of ischemia resolved in all (7/17) animals with increased or normal perfusion on their final scan. Scintigraphy provided a safe and noninvasive assessment of distal limb perfusion, which corresponded with clinical outcome.

A thermal clearance probe for continuous monitoring of cerebral blood flow.

Cortical thermal clearance provides a practical means of continuous assessment of cerebral blood flow. A probe which can be used to monitor cerebral cortical thermal clearance is described. It has proved a reliable method of predicting oligaemia, showing good correlation between measured thermal clearance and the onset of clinical signs of ischaemia. The limitations are its size, invasiveness, small sample volume and difficulty with quantification. It is a useful additional tool in the management of patients suffering from acute neurosurgical disorders.

Preoperative prediction of cerebral ischaemia due to carotid occlusion

The vast majori ty of patients tolerate clamping of the carotid artery, wi thout signs of cerebral ischaemia. There is no doubt , however , that a subgroup of pat ients exists wi th insufficient collateral circulation w h o will develop ischaemia wi thout protect ive measures , and this is seen most clearly in those patients w h o undergo carotid endar te rec tomy u n d e r local anaesthesia, 10-15% of w h o m have clinical signs of ischaemia when the carotid ar tery is c lamped (Table 1). Similar figures are seen wi th electroencephalogram (EEG) recording w h e n the operat ion is pe r fo rmed u n d e r general anaesthesia, and in cases wi th contralateral occlusion, some 20-25% will have signs of hypoper fus ion dur ing clamping. Even though few of these patients will develop a stroke w h e n the operat ion is per formed wi thout a shunt ,

Muscle ATP and lactate and the release of myoglobin and carbanhydrase III in acute lower-limb ischaemia

Serum-myoglobin and carbanhydrase III (S-CAIII), a specific muscle enzyme, were measured on admission, during surgery and in the postoperative period in 23 patients with acute lower-limb ischaemia and in 21 patients with chronic limb ischaemia in order to evaluate these molecules as possible markers of the degree of clinical ischaemia. The muscle contents of ATP and lactate were determined in muscle biopsies from patients with acute ischaemia on admission. Unlike S-myoglobin and S-CAIII they discriminated between cases which required subsequent amputation from those which did not. Clinical signs of ischaemia were, however, of no value in this respect and there were no correlations between clinical signs or the duration of ischaemia and S-myoglobin or S-CAIII or the contents of ATP or lactate in muscle tissue. The levels of S-myoglobin and S-CAIII correlated well (r = 0.95, p less than 0.0001). In patients who subsequently required an amputation S-myoglobin increased ten-fold (i.e., from 24-48 h postoperatively in acute arterial ischaemia and from 3 h postoperatively in patients with chronic limb ischaemia). In patients with a successful revascularisation S-myoglobin returned to normal levels. It is concluded that in this investigation S-myoglobin had no prognostic value on admission and that S-myoglobin analyses in the postoperative course may be useful for making clinical decisions concerning impending recirculation failures.

Lack of ouabain effect on pacing-induced myocardial ischemia in patients with coronary artery disease

Sixteen patients with significant two and three vessel coronary artery disease but without clinical congestive heart failure were studied during rapid atrial pacing before and after infusion of 0.015 mg/kg of ouabain. Seven patients with a decreased (less than 50 percent) election fraction and nine patients with a normal election fraction had a significant ( P < 0.05) increase in resting arterial systolic pressure after the administration of ouabain. However, resting values for coronary sinus flow, coronary vascular resistance, myocardial oxygen consumption and myocardial lactate extraction did not change significantly in either group. During pacing, patients with a decreased ejection fraction demonstrated more ischemia than patients with a normal ejection fraction; however, the administration of ouabain did not significantly alter pacing-related changes in coronary sinus flow, myocardial oxygen consumption, myocardial lactate extraction, ischemic electrocardiographic changes or onset of chest pain in either group. The administration of ouabain has a negligible effect on coronary hemodynamics, myocardial metabolism or clinical signs of ischemia in patients with coronary artery disease with normal or abnormal left ventricular function.