Post-angioplasty far infrared radiation therapy improves 1-year angioplasty-free hemodialysis access patency of recurrent obstructive lesions.

OBJECTIVE: To explore the role of far infrared (FIR) radiation therapy for hemodialysis (HD) access maintenance after percutaneous transluminal angioplasties (PTA). METHODS: This was a prospective observational study. Eligible patients were those who received repeated PTA with the last PTA successfully performed within 1 week before the study enrollments. Consecutively enrolled patients undergoing successful HD treatments after PTA were randomly assigned to the FIR-radiated group or control group without radiation. FIR-radiated therapy meaning 40-minute radiation at the major lesion site or anastomosed site three times a week was continued until an end-point defined as dysfunction-driven re-PTA or the study end was reached. RESULTS: Of 216 participants analyzed, including 97 with arteriovenous grafts (AVG) (49 FIR-radiated participants and 48 control participants) and 119 with arteriovenous fistulas (AVF) (69 FIR-radiated participants and 50 control participants), the FIR-radiated therapy compared with free-radiated usual therapy significantly enhanced PTA-unassisted patency at 1 year in the AVG subgroup (16.3% vs. 2.1%; p < .01), but not the AVF subgroup (25.0% vs. 18.4%; p = .50), and this accounted for the overall improved patency rates (21.4% vs. 10.3%; p = .02). CONCLUSIONS: This study suggests FIR-radiated therapy improves PTA-unassisted patency in patients with AVG who have undergone previous PTA.

Does inadequate exercise lower the accuracy of myocardial perfusion scintigraphy?

The predictive accuracy of exercise myocardial perfusion scintigraphy (EMPS) in detecting coronary artery disease (CAD) in patients who fail to achieve an adequate level of exercise is not clear. This investigation was carried out in order to compare the sensitivity, specificity and accuracy of EMPS in adequate exercise patients with those in inadequate exercise patients. We have retrospectively compared the results of EMPS with coronary angiography (CAG). One hundred and forty-eight patients with both tests within 6 weeks were included. Adequate exercise was defined as > or = 85% maximally predicted heart rate for age. The overall sensitivity and specificity of EMPS to detect CAD were 92.5% (74/80) and 75%, (51/68), respectively. The sensitivity and specificity in adequate exercise patients were 94.1% (32/34) and 67.6% (23/34), whereas those in inadequate exercise patients were 91.3% (42/46) and 82.4% (28/34). The accuracy was 80.9% (55/68) and 87.5% (70/80), respectively. Patients with inadequate exercise had lower sensitivity but higher specificity of EMPS for detecting CAD, and achieved a higher accuracy than those with adequate exercise.

New stenosis on proximal coronary segment after directional atherectomy. Two case reports.

Two patients with new coronary stenotic lesions subsequently developed proximal to the sites accepting directional coronary atherectomy (DCA) are reported. One lesion developed at the left main coronary artery and the other at the proximal segment of the left anterior descending artery. The mechanisms of the development of such new stenotic lesions after DCA were studied and procedure-related mechanical trauma over the proximal segment of the primary lesion may be the possible mechanism for such complication.

Differentiating syndrome X from coronary artery disease by treadmill exercise test in patients with chest pain and exercise-induced myocardial ischemia.

Even though the underlying mechanisms of myocardial ischemia may be different, it is difficult to differentiate syndrome X from coronary artery disease (CAD) by means of the treadmill exercise test in elderly patients with chest pain and exercise-induced myocardial ischemia. One hundred sex- and age-matched patients-42 with syndrome X and 58 with CAD-were studied. Another 10 subjects with atypical chest pain, negative treadmill exercise test, and normal-appearing coronary angiograms served as controls. We evaluated the difference in exercise performance between patients with syndrome X and CAD, and the treadmill exercise test was undertaken with modified Bruce protocol within 2 weeks before coronary angiography. Parameters including time to 1 mm ST segment depression (STD), exercise duration (ED), heart rate (HR), systolic blood pressure, rate-pressure product (RPP), and percentage of age-predicted maximum HR (% HR) at different stages of the test were measured and then compared among the three groups of patients. Compared with CAD patients, syndrome X patients had significantly higher HR, % HR, and RPP at the time of 1 mm STD and at peak exercise. The time to 1 mm STD and ED were longer in syndrome X than in CAD patients. However, ED was shorter and HR, % HR, and RPP at peak exercise were similar in syndrome X patients as compared with control subjects. The new criterion of combined ED (> or =315 seconds) and RPP at peak exercise (> or =24,000 beats x mmHg/min) was found to be highly specific (86%) and moderately sensitive (64%) in differentiating syndrome X from CAD patients. The positive likelihood ratio for this criterion was 4.57 and negative likelihood ratio was 0.42. In conclusion, syndrome X patients had better exercise performance than CAD patients, but less ED and similar workload when compared with control subjects. The new criterion proposed in this study may provide a quick and simple way to differentiate syndrome X from CAD in a group of aged and predominantly male patients with chest pain and positive treadmill exercise test.

Computerized-tomography-guided percutaneous tumor ablation using acetic acid injection in an aldosterone-producing tumor--a novel therapy.

We report the first case of an adrenocortical tumor that was successfully ablated using computerized tomography (CT)-guided percutaneous acetic acid injection. A 57-year-old woman presented with recurrent sudden onset of general weakness, polyuria, hypokalemia and low plasma renin activity with a high aldosterone level. The computerized tomogram and sonogram of the abdomen demonstrated a well-defined low-density tumor in the right adrenal gland. Under CT guidance, we successfully ablated the tumor using percutaneous acetic acid injection. This procedure took only 40 minutes and required only local anesthesia. The patient was up and walking the following day. During the next 2 years of clinical follow-up, there was no evidence of tumor recurrence.

Different exercise performance between aged patients with syndrome X and those with coronary artery disease.

BACKGROUND: Both patients with coronary artery disease (CAD) and those with syndrome X (anginal chest pain, exercise-induced myocardial ischemia, normal coronary angiogram and no evidence of coronary spasm) have ischemic electrocardiogram (ECG) during exercise. However, the difference of ECG change during treadmill exercise test in these two patient groups has rarely been studied. METHODS: In this prospective study, we evaluated and compared the changes of hemodynamics and 12-lead ECG during treadmill exercise test by modified Bruce protocol in 29 patients with syndrome X and 46 patients with CAD. RESULTS: As compared with CAD patients, syndrome X patients had significantly higher heart rate, higher systolic blood pressure and higher rate-pressure product at 1mm ST depression and peak exercise. The time to 1mm ST depression (304 +/- 128 vs 254 +/- 92 seconds, p = 0.06) and total exercise duration (463 +/- 108 vs 331 +/- 111 seconds, p < 0.001) were also longer in syndrome X than in CAD patients. However, coronary flow reserves, obtained from 20 syndrome X patients and 9 CAD patients, did not differ between both groups. (2.3 +/- 0.6 vs 2.5 +/- 0.6, p = NS) CONCLUSIONS: Patients with syndrome X had higher ischemic threshold and better exercise tolerance than CAD patients though coronary flow reserve was similar between them. During exercise, more work-load as well as metabolic demands was required for the development of similar degree of myocardial ischemia in these aged syndrome X patients as compared with CAD patients.

Significance of cardiac troponin I and creatine kinase release after coronary intervention.

BACKGROUND: Cardiac troponin I is a highly sensitive and specific marker for early detection of myocardial injury. Whether it can be used to monitor myocardial injury after coronary intervention is uncertain. This study was designed to measure the cardiac troponin I and creatine kinase (CK) after coronary intervention and investigate their clinical significance. METHODS: We measured cardiac troponin I and CK levels before intervention and 4 hours, 8 hours, 12 hours and 24 hours after apparently successful coronary intervention in 106 eligible patients. Nine patients were excluded due to missing data. We also followed up the clinical outcome to record major cardiac events (MACE). RESULTS: The frequency of cardiac troponin I increase after coronary intervention was higher than that of CK increase (40.2% vs 8.2%). The frequency of cardiac troponin I increase in the stent group was significantly higher than that in the PTCA group (49.2% vs 21.9%, p < 0.001). The frequency of cardiac troponin I increase was also higher than that of CK increase in patients with in-hospital events (58.8% vs 14.7%). CONCLUSIONS: Cardiac troponin I is more sensitive than creatine kinase in detecting myocardial injury after coronary intervention. The incidence of cardiac troponin I increase is significantly higher in patients undergoing stenting than in patients treated with balloon angioplasty only. The cardiac troponin I increase is more highly correlated with in-hospital events than is creatine kinase.

Electron microscopic studies of phenotypic modulation of smooth muscle cells in coronary arteries of patients with unstable angina pectoris and postangioplasty restenosis.

BACKGROUND: Proliferation and matrix protein secretion of coronary smooth muscle cells (SMCs) have been suggested as one of the mechanisms responsible for the development of postangioplasty restenosis and an alternative cause of unstable angina. Phenotypic modulation of SMCs may produce a pool of cells potentially responsive to growth stimulation that can synthesize abundant extracellular matrix. This study tested the hypothesis that phenotypic modulation of SMCs occurred during the evolution of postangioplasty restenosis and unstable angina. METHODS AND RESULTS: The SMCs of coronary atherectomy specimens from 24 patients were identified under electron microscope. Volume fractions of synthetic organelles (VFSOs) and other features related to phenotypic modulation of SMCs were measured. The results showed that the VFSO in SMCs from 5 patients with unstable angina (group 2) resembled those from 9 patients with postangioplasty restenosis (group 3; 0.42 +/- 0.13 versus 0.36 +/- 0.10; P = NS), and both were significantly higher than those from 6 patients with stable angina (group 1; 0.21 +/- 0.11). Four patients with restenosis lesions who underwent angioplasty > 6 months ago (group 4) also had a low VFSO in SMCs (0.19 +/- 0.05). This value was significantly less than those in groups 2 and 3 (P < .05) but similar to that in group 1. CONCLUSIONS: The coronary lesions from patients with unstable angina resembled those from patients with postangioplasty restenosis in terms of the phenotypic modulation and VFSO in SMCs. Our findings therefore suggest that after phenotypic modulation, the SMCs may become responsive to growth stimulation, with an ability to massively proliferate and synthesize abundant extracellular matrix. These processes may lead to plaque expansion and eventually to the development of unstable angina and restenosis.

Coronary microvascular dysfunction is associated with ischemic-like electrocardiogram during exercise in patients with anginal chest pain and normal coronary angiograms.

To determine the possible mechanism of the ischemic-like electrocardiogram (ECG) during exercise in the presence of anginal chest pain and normal coronary angiograms, both a treadmill exercise test (TET) and coronary hemodynamic study were prospectively performed in 33 consecutive patients (18 females and 15 males, aged 48 +/- 10 years) with angina of unknown cause. Although baseline characteristics and coronary hemodynamics were similar between patients with (TET+, n = 17) and those without (TET-, n = 16) ischemic-like ECG during TET, effort angina was more frequently seen in the former group (p < 0.01). Compared to TET- patients, TET+ patients had a significantly lower maximum great cardiac vein flow (GCVF, 108.8 +/- 47.0 vs 146.4 +/- 23.4 ml/min, p = 0.007), higher minimum coronary vascular resistance (0.94 +/- 0.41 vs 0.61 +/- 0.09 mmHg/ml/min., p = 0.003), and lower corrected GCVF (GCVF/rate-pressure product, 0.0087 +/- 0.0036 vs 0.0125 +/- 0.0019, p = 0.001) after dipyridamole infusion (0.56 mg/kg for 4 min). Though coronary flow reserve was significantly lower in TET+ than in TET- patients (2.26 +/- 0.59 vs 3.08 +/- 0.48, p = 0.0001), myocardial oxygen consumption and myocardial efficiency (rate-pressure product/myocardial oxygen consumption) were still similar between these two groups after dipyridamole infusion. Thus, coronary microvascular dysfunction rather than altered cardiac metabolism could contribute to effort angina and ischemic-like ECG during exercise in patients with anginal chest pain and normal coronary angiograms.

Early alteration of coronary hemodynamics in late restenosis after coronary angioplasty.

It is not known whether changes in coronary hemodynamics may antedate the development of restenosis after percutaneous coronary transluminal angioplasty (PTCA). The purpose of this study was to evaluate the early change in coronary microvascular function in patients with late restenosis after PTCA. Coronary hemodynamics were studied in series before, immediately after, 2 weeks and 3 months after successful PTCA in 12 male patients with a single lesion of the left anterior descending coronary artery. In each patient, great cardiac venous flow (GCVF) and oxygen content were measured both at baseline and during hyperemia induced by adenosine infusion. The sequential changes of coronary hemodynamics were compared between patients with and without restenosis at 3 months after PTCA. Basic characteristics did not differ between the patients with (n = 6) and those without restenosis (n = 6). Luminal diameter stenosis (in percentage) was also similar between the two groups both before (79.2 +/- 18.4% vs 83.0 +/- 9.6%, p = NS) and up to 2 weeks after PTCA (25.8 +/- 10.9% vs 28.5 +/- 7.9%, p = NS). In patients without restenosis, basal and hyperemic GCVF was unchanged up to 2 weeks after PTCA. There was a significant increase in CFR 3 months after PTCA. In patients with restenosis, basal GCVF was significantly increased and hyperemic GCVF was unchanged immediately after PTCA. However, 2 weeks after PTCA, basal GCVF was decreased while luminal diameter was still preserved. In comparison with those without restenosis, patients with restenosis had significantly lower CFR before (1.98 +/- 0.42 vs 2.69 +/- 0.46, p = 0.019), immediately after (1.47 +/- 0.27 vs 2.24 +/- 0.47, p = 0.006) and 3 months after PTCA (1.51 +/- 0.32 vs 3.40 +/- 0.54, p = 0.001). In patients without restenosis, the recovery of coronary microvascular function was delayed up to 3 months after PTCA. In patients with late restenosis, basal coronary microvascular tone was altered within 2 weeks after PTCA suggesting early deterioration of coronary microvascular function before the development of angiographic restenosis.

Transthoracic and transesophageal echocardiographic diagnosis of aneurysm of the sinus of Valsalva: a review of five year experience.

BACKGROUND: Aneurysms of the sinus of Valsalva (SVA) are uncommon congenital lesions. The clinical presentations vary from asymptomatic to progressive heart failure following rupture of the aneurysm into an adjacent cardiac chamber. Retrograde aortogram is the diagnostic tool of choice preoperatively. Recent studies have demonstrated that the SVA can be accurately diagnosed using transthoracic two-dimensional, and color Doppler flow mapping, even for surgical preparation without cardiac catheterization. We report our 5-year experience of transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) in the evaluation of SVA. METHODS: Eleven adult patients with SVA with or without rupture were studied using both TTE and TEE. All of the diagnoses were subsequently comfirmed by either cardiac catheterization or surgical findings. RESULTS: Aneurysms originated in the right coronary sinus (n = 9) and noncoronary sinus (n = 2); they ruptured into the right ventricle in 5 patients and the right atrium in 5 patients. An unruptured right SVA was noted in 1 patient. Both TTE and TEE could identify the site of the aneurysm, rupture sites, and the receiving chamber equally well. Co-existent cardiac lesions included 11 cases of valvular aortic regurgitation (mild in 7, moderate in 2 and severe in 2). Two cases of perimembranous type ventricular septal defect (VSD) and 6 cases of supracristal type VSD (including 1 case of tetraology of Fallot, 3 supracristal, 1 muscular and 1 subaortic) were noted. Three cases were complicated with valvular vegetations (1 aortic valve, 1 aortic and tricuspid valve and 1 aortic and pulmonic valve). One patient had patent ductus arteriosus and 2 patients had pulmonic valvular stenosis. CONCLUSIONS: TEE provides clearer definition for the detailed anatomy of the ruptured sac and co-existent cardiac lesions than TTE through high resolution and closer approach. We conclude that TEE is a powerful complementary diagnostic tool in the evaluation of patients with SVA. TEE also provides additionally useful information for guiding the surgical approach and for assessing the operative results even without cardiac catheterization.