Monitoring cerebral oxygenation during balloon occlusion with multichannel NIRS

We report on oxygenation changes noninvasively recorded by multichannel continuous-wave near infrared spectroscopy (CW-NIRS) during endovascular neuroradiologic interventions requiring temporary balloon occlusion of arteries supplying the cerebral circulation. Digital subtraction angiography (DSA) provides reference data on the site, timing, and effectiveness of the flow stagnation as well as on the amount and direction of collateral circulation. This setting allows us to relate CW-NIRS findings to brain specific perfusion changes. We focused our analysis on the transition from normal perfusion to vessel occlusion, i.e., before hypoxia becomes clinically apparent. The localization of the maximal response correlated either with the core (occlusion of the middle cerebral artery) or with the watershed areas (occlusion of the internal carotid artery) of the respective vascular territories. In one patient with clinically and angiographically confirmed insufficient collateral flow during carotid artery occlusion, the total hemoglobin concentration became significantly asymmetric, with decreased values in the ipsilateral watershed area and contralaterally increased values. Multichannel CW-NIRS monitoring might serve as an objective and early predictive marker of critical perfusion changes during interventions—to prevent hypoxic damage of the brain. It also might provide valuable human reference data on oxygenation changes as they typically occur during acute stroke.     

Prognostic value of early exercise testing after coronary stent implantation

The clinical value of early exercise stress testing (EST) after coronary stenting to predict long-term clinical outcomes is unknown. Of 1,000 unselected patients who underwent coronary stenting, 446 random patients underwent early EST the day after intervention. Clinical long-term outcomes (41 +/- 20 months) were correlated with normal (n = 314 [70%]) or positive (n = 102 [23%]) EST results. Patients with inconclusive test results (n = 30 [7%]) were excluded from the analysis. Overall mortality was significantly higher in patients with positive EST results (9.3% vs 3.9%, p = 0.04). Major adverse cardiac events and cardiac mortality also tended to be higher in patients with positive stress test results (45.4% vs 35.4%, p = 0.08, and 4.1% vs 1.1%, p = 0.05, respectively). Patients with the combination of positive stress test results and incomplete revascularization appeared to be the group at highest risk for major adverse cardiac events (47.1% vs 33.3% for patients with normal stress test results and complete revascularization, p = NS). Negative stress test results reduced (odds ratio 0.329, 95% confidence interval 0.120 to 0.905, p = 0.031) and a lower ejection fraction increased (odds ratio 0.942, 95% confidence interval 0.897 to 0.989, p = 0.017) the risk for death. In conclusion, an early stress test after coronary stenting provides important prognostic information. Positive stress test results, especially in combination with incomplete revascularization, are associated with higher mortality, a trend toward more repeat revascularization procedures, and higher risk for major adverse cardiac events.     

Non-invasive diagnosis of coronary artery disease using cardiogoniometry performed at rest

PRINCIPLES: Cardiogoniometry is a non-invasive technique for quantitative three-dimensional vectorial analysis of myocardial depolarization and repolarization. We describe a method of surface electrophysiological cardiac assessment using cardiogoniometry performed at rest to detect variables helpful in identifying coronary artery disease. METHODS: Cardiogoniometry was performed in 793 patients prior to diagnostic coronary angiography. Using 13 variables in men and 10 in women, values from 461 patients were retrospectively analyzed to obtain a diagnostic score that would identify patients having coronary artery disease. This score was then prospectively validated on 332 patients. RESULTS: Cardiogoniometry showed a prospective diagnostic sensitivity of 64%, and a specificity of 82%. ECG diagnostic sensitivity was significantly lower, with 53% and a similar specificity of 75%. CONCLUSIONS: Cardiogoniometry is a new, noninvasive, quantitative electrodiagnostic technique which is helpful in identifying patients with coronary artery disease. It can easily be performed at rest and delivers an accurate, automated diagnostic score.     

Coronary collateral perfusion in patients with coronary artery disease: effect of metoprolol.

BACKGROUND: The use of ultrathin Doppler angioplasty guidewires has made it possible to measure collateral flow quantitatively. Pharmacologic interventions have been shown to influence collateral flow and, thus, to affect myocardial ischaemia. METHODS: Twenty-five patients with coronary artery disease undergoing PTCA were included in the present analysis. Coronary flow velocities were measured in the ipsilateral (n = 25) and contralateral (n = 6; two Doppler wires) vessels during PTCA with and without i.v. adenosine (140 microg/kg.min) before and 3 min after 5 mg metoprolol i.v., respectively. The ipsilateral Doppler wire was positioned distal to the stenosis, whereas the distal end of the contralateral wire was in an angiographically normal vessel. The flow signals of the ipsilateral wire were used to calculate the collateral flow index (CFI). CFI was defined as the ratio of flow velocity during balloon inflation divided by resting flow. RESULTS: Heart rate and mean aortic pressure decreased slightly (ns) after i.v. metoprolol. The collateral flow index was 0.25+/-0.12 (one fourth of the resting coronary flow) during the first PTCA and 0.27+/-0.14 (ns versus first PTCA) during the second PTCA, but decreased with metoprolol to 0.16+/-0.08 (p<0.0001 vs. baseline) during the third PTCA. CONCLUSIONS: Coronary collateral flow increased slightly but not significantly during maximal vasodilatation with adenosine but decreased in 23 of 25 patients after i.v. metoprolol. Thus, there is a reduction in coronary collateral flow with metoprolol, probably due to an increase in coronary collateral resistance or a reduction in oxygen demand.     

Mediator release after nasal airway challenge with allergen

An in vivo model of human allergic disease has been developed in which nasal challenge with antigen leads to physiologic changes, together with a release of increased amounts of inflammatory mediators into nasal secretions obtained by washing the nose with saline. In 105 experiments involving 35 subjects, only allergic subjects consistently demonstrated an increase in the concentrations of the mast cell mediator, histamine, and the putative mast cell mediators, TAME-esterase and PGD2. The release of each mediator was significantly (p less than 0.001) related to the physiologic change (sneezing). The release of each mediator also correlated significantly with the release of the other 2 mediators (p less than 0.001). This system, for the first time, clearly relates an in vivo symptom and mediator release and thus should provide an excellent tool for the further study of the allergic response and nasal pathophysiology.     

Paradoxical emboli through the patent foramen ovale as the suspected cause of myocardial and renal infarction in a 48-year-old woman.

We review the case of a 48-year-old woman who underwent elective percutaneous patent foramen ovale closure following successive renal and myocardial infarction with normal renal and coronary arteries, probably as a consequence of paradoxical emboli.     

Coronary dissection and total coronary occlusion associated with percutaneous transluminal coronary angioplasty: significance of initial angiographic morphology of coronary stenoses

Coronary dissection and total coronary occlusion leading to emergency coronary surgery are the most frequent complications of percutaneous transluminal coronary angioplasty (PTCA) and their occurrence usually is unpredictable. To identify angiographic characteristics of coronary stenoses that may affect the incidence of these complications, the diagnostic pre-PTCA coronary angiograms of 38 consecutive patients (group I) undergoing emergency coronary surgery for dissection or occlusion were reviewed and compared with the angiograms of a random sample of 38 patients (stratified for left anterior descending and right coronary arteries) from a group of 1151 who did not need emergency coronary surgery (group II). Stenosis morphology before angioplasty was considered "complicated" if at least one of the following criteria was present: irregular borders, intraluminal lucency, and localization of stenosis in curve or at bifurcation. Baseline characteristics, maximum inflation pressures, types of balloon catheters used, and routinely registered angiographic stenosis properties (severity, length, eccentricity, and calcification) were similar in both groups. Irregular borders before PTCA were present in 22 of 38 patients in group I vs 10 of 38 in group II (p less than .05), intraluminal lucency in 22 of 38 vs nine of 38 (p less than .05), localization in curve in 27 of 38 pts vs 16 of 38 (p less than .05), and localization at bifurcation in 11 of 38 vs 15 of 38 (NS). Complicated angiographic morphology of coronary stenosis may represent a risk factor for dissection or occlusion. Therefore, although the predictive value of these findings is low, detailed evaluation of angiographic morphology of coronary stenoses may improve patient selection and reduce complication rates of PTCA.