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Biomedical subjects

U Deligonul

Publications and source records attributed to U Deligonul.

At least 55 records · Page 3Linked to original sources
PubMed1991

Influence of radiographic contrast media viscosity to flow through coronary angiographic catheters.

To assess the influence of viscosity on flow resistance, 4 clinically available contrast media were injected through 12 angiographic catheters of varying dimensions at 20 degrees and 37 degrees C. Seven cc of contrast was injected at a pressure of 200 PSI at 3cc/sec by Medrad Mark IV power injector. The pressure of injection through the manifold was recorded with an electronic pressure transducer. The lowest injection pressure at 37 degrees C occurred with Hexabrix. Differences in contrast media viscosity were apparent with catheters less than 6 French diameter. There were minimal differences in injection pressures with regard to the coronary curve tip configurations for any of the contrast agents. At 20 degrees C, Isovue had lower injection pressures than the other contrast agents. Injection through 5 French catheters demonstrated a greater than 1.5 atmosphere difference, especially between Omnipaque and Hexabrix. The difference in contrast media injection pressure was greater than 2 atmospheres between 8 French guiding and 8 French diagnostic catheters and between 5 French and 6 French diagnostic catheters and less than 2 atmospheres between 8 French and 6 French diagnostic catheters. Injection pressure differences greater than 1 atmosphere were not observed for catheters of the same French size at body or room temperature contrast injection. These data indicate that important temperature related viscosity differences between agents are present and confirm that the largest differences in contrast media are most apparent for the smallest diameter catheters. Given equivalent image opacification and hemodynamic and adverse effects, selection of a low viscosity contrast media theoretically provides an advantage during procedures using small diameter catheters or interventional procedures requiring contrast media visualization through reduced channels.

Angiography↗
PubMed1991

Accordion right coronary artery: an unusual complication of PTCA guidewire entrapment.

The contour of the epicardial coronary vessels may change considerably during coronary angioplasty. We report the extreme and unique "accordion-like" wrinkling of the mid right coronary artery as a result of distal guidewire entrapment during coronary angioplasty. Recognition of this artifact and its treatment may prevent further complications of coronary angioplasty.

Aged↗
PubMed1991

Interpretation of cardiac pathophysiology from pressure waveform analysis: the left-sided V wave.

The left-sided V wave is dependent on both left atrial and ventricular pressure/volume filling relationship. The cardiac rhythm and timing of atrial systole also influences the V wave. The morphology of the V wave can reflect the severity of mitral regurgitation with stenosis, but valve areas in this setting may be better assessed by a pressure half-time method. Finally, as queried in our first patient example, V wave alternans is a reflection of left ventricular pressure alternans in a failing heart. Other signs of poor left ventricular function in Figure 1 also included an elevated minimal diastolic pressure and markedly elevated left ventricular end diastolic pressure. Hemodynamic findings of poor left ventricular function will be addressed in detail in a later "Rounds."

Aged↗
PubMed1991

Interpretation of cardiac pathophysiology from pressure waveform analysis: pacemaker hemodynamics.

The abnormal sequence of A-V contraction produces alteration of right and left heart hemodynamics reflecting the inappropriate timing of atrial contraction to ventricular filling. Some symptomatic patients may require A-V sequential pacing to improve cardiac output. The clinical effects of the atrial contribution to left ventricular function can be demonstrated by careful review of hemodynamic tracings in these individuals.

Aged↗
PubMed1991

Interpretation of cardiac pathophysiology from pressure waveform analysis: percutaneous balloon valvuloplasty.

The hemodynamic findings of aortic, mitral and pulmonary balloon valvuloplasty serve to identify classical valvular lesions and their responses to graded or abrupt catheter dilation techniques. The production of mild insufficiency after valve dilation is generally well tolerated. Severe valvular insufficiency produces the expected hemodynamic alterations, but acute decompensation may be witnessed over brief periods of time. The use of extra stiff guidewires across dilated valves, especially the aortic valve, may also produce an exaggerated hemodynamic picture of insufficiency. Although gradients may be reduced, the effect of valve dilation on aortic valve area is generally small. A discussion of factors influencing valve area calculations will be the subject of a future "Rounds."

Blood Pressure↗
PubMed1991

The effects of high (sodium meglumine diatrizoate, Renografin-76) and low osmolar (sodium meglumine ioxaglate, Hexabrix) radiographic contrast media on diastolic function during left ventriculography in patients.

Although a majority of studies indicate superior hemodynamic and clinical profiles of low osmolar compared with high osmolar contrast media, the effect of these agents on diastolic left ventricular function has not been examined. We prospectively examined hemodynamic, electrocardiographic, and echocardiographic indices of left ventricular function in patients undergoing contrast ventriculography with a high osmolar, ionic, monomeric contrast, diatrizoate (Renografin-76) compared with a low osmolar, ionic, dimeric contrast, ioxaglate (Hexabrix). Thirty patients were randomized to each group. There were no clinical differences between the two groups. The decrease in systemic pressures was significantly greater with diatrizoate after left ventriculography (-38.5 +/- 3.5 versus -18.2 +/- 2.3, p less than 0.001) and selective left coronary angiography (-29.5 +/- 2.4 versus -17.4 +/- 2.6, p less than 0.001). In addition, left ventricular end-diastolic pressure increased significantly more with diatrizoate (7.3 +/- 0.9 versus 2.7 +/- 0.8 mm Hg for ioxaglate, p less than 0.001). QT interval prolongation occurred in both patient groups. Diatrizoate decreased systemic vascular resistance, and increased cardiac output and left ventricular ejection fraction more than ioxaglate, while simultaneously increasing left ventricular end-diastolic volume and altering the peak atrial filling velocity. Negative dp/dt (p less than 0.05), but not Tau, computed by the logarithmic or derivative methods, was reduced by diatrizoate. These data indicate that significant alteration of diastolic filling patterns occurs with high osmolar compared with low osmolar contrast agents. Although the clinical significance of this observation is currently unknown, these data further support the reported hemodynamic superiority of the low osmolar, dimeric contrast agent ioxaglate during contrast angiography.

Contrast Media↗
PubMed1991

Intravenous adenosine: continuous infusion and low dose bolus administration for determination of coronary vasodilator reserve in patients with and without coronary artery disease.

To assess the use of adenosine as an alternative agent for determination of coronary vasodilator reserve, hemodynamics and coronary blood flow velocity were measured at rest and during peak hyperemic responses to continuous intravenous adenosine infusion (50, 100 and 150 micrograms/kg per min for 3 min) and intracoronary papaverine (10 mg) in 34 patients (17 without [group 1] and 17 with [group 2] significant left coronary artery disease), and in 17 patients (11 without and 6 with left coronary artery disease) after low dose (2.5 mg) intravenous bolus injection of adenosine. The maximal adenosine dose did not change mean arterial pressure (-10 +/- 14% and -6 +/- 12% for groups 1 and 2, respectively) but increased the heart rate (15 +/- 18% and 13 +/- 16, respectively). For continuous adenosine infusions, mean coronary flow velocity increased 64 +/- 104%, 122 +/- 94% and 198 +/- 59% and 15 +/- 51%, 110 +/- 95% and 109 +/- 86% in groups 1 and 2, respectively for each of the three doses. Mean coronary flow velocity increased significantly after 100 and 150 micrograms/kg of adenosine and 10 mg of intracoronary papaverine (48 +/- 25, 52 +/- 19 and 54 +/- 21 cm/s, respectively; all p less than 0.05 vs. baseline) and was significantly higher than in group 2 (37 +/- 24, 32 +/- 16, 41 +/- 23 cm/s; all p less than 0.05 vs. group 1). The coronary vasodilator reserve ratio (calculated as the ratio of hyperemic to basal mean flow velocity) for adenosine and papaverine was 2.94 +/- 1.50 and 2.94 +/- 1.00, respectively, in group 1 and was significantly and similarly reduced in group 2 (2.16 +/- 0.81 and 2.38 +/- 0.78, respectively; both p less than 0.05 vs. group 1). Low dose bolus injection of adenosine increased mean velocity equivalently to that after continuous infusion of 100 micrograms/kg, but less than after papaverine. There was a strong correlation between adenosine infusion and papaverine for both mean coronary flow velocity and coronary vasodilator reserve ratio (r2 = 0.871 and 0.325; SEE = 0.068 and 0.189, respectively; both p less than 0.0005). No patient had significant arrhythmias or prolongation of the corrected QT (QTc) interval with adenosine, but papaverine increased the QT (QTc) interval from 445 +/- 44 to 501 +/- 43 ms (p less than 0.001 vs. both maximal adenosine and baseline) and produced nonsustained ventricular tachycardia in one patient.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenosine↗
PubMed1991

Determinants of 2-year outcome after coronary angioplasty in patients with multivessel disease on the basis of comprehensive preprocedural evaluation. Implications for patient selection. The Multivessel Angioplasty Prognosis Study Group.

BACKGROUND: To assess the likelihood of intermediate-term event-free survival (freedom from death, coronary artery bypass surgery, and myocardial infarction) in patients with multivessel coronary disease undergoing coronary angioplasty, 350 consecutive patients from four clinical sites were carefully evaluated and followed for 22 +/- 10 months. METHODS AND RESULTS: Eight clinical variables were evaluated at the clinical sites, and 23 angiographic variables describing the number, morphology, and topography of coronary stenoses were evaluated at a core angiographic laboratory. Most patients had Canadian Cardiovascular Society class III or IV angina (72%), two-vessel coronary disease (68%), and well-preserved left ventricular function (mean ejection fraction, 58 +/- 12%; range, 18-85%). Follow-up was complete in 99% of patients. At 2 years, event-free survival was 72%, overall survival was 96%, freedom from bypass surgery was 82%, and freedom from nonfatal myocardial infarction without surgery was 96%. Sequential Cox proportional hazards regression analyses allowing stepwise entry of variables prospectively coded as simple, as of intermediate complexity, or as complex found event-free survival to be independently predicted by low Canadian Cardiovascular Society angina class, no diabetes, no proximal left anterior descending stenoses, and the sum of stenosis simplified risk-territory scores of 15 or less. In the absence of class IV angina and these risk factors, 2-year event-free survival was 87% and overall survival was 100%. In the presence of two or more of these risk factors, event-free survival was less than 50%. CONCLUSIONS: Recognition of risk factors for poor long-term outcome in this setting may improve clinical decision making and provide a framework on which to base meaningful subgroup analyses in randomized trials assessing the efficacy of coronary angioplasty.

Angioplasty, Balloon, Coronary↗