Evaluation of DNA damage in lymphocytes of cardiologists exposed to radiation during cardiac catheterization by the COMET ASSAY.

This study was designed to evaluate the possible in vivo induction of DNA damage by exposure to radiation in cardiologists. The alkaline comet assay (single cell gel electrophoresis, SCGE), which appears to be a promising tool with which to estimate DNA damage at the single cell level, has been used. The assay was carried out on 30 cardiologists currently employed in a busy cardiac service and 30 healthy unexposed controls. Venous blood samples were obtained from the exposed and control subjects and SCGE was examined in 100 cells graded as undamaged, intermediate, and tailed nuclei. The number of undamaged nuclei was almost the same in control and exposed subjects. The extent of DNA migration (SCGE assay) did not distinguish between the samples in either the nonsmoker exposed or nonsmoker control subjects, which leads one to wonder whether a difference in DNA damage really exists. Previous studies reported increased DNA damage in blood lymphocytes of smokers. In our study, the percentage of damaged cells increased either with the frequency of smoking or exposure to radiation. A statistically significant difference was observed both in smokers and exposed subjects. In conclusion, the elevated grade of DNA damage in cardiologists exposed to radiation indicates a possible genotoxic hazard, therefore, careful measures and full cooperation between cardiologists and radiologists should be undertaken to reduce the exposure to radiation.

Early and late outcome of stenting in a consecutive series of patients with coronary lesions in vessels less than 2.8 mm in diameter.

In an attempt to determine the early and late outcomes of small vessel stenting, we retrospectively evaluated our database on 51 consecutive patients (41 males, mean age, 57.1 +/- 10.1 years) who underwent stenting of at least one significant lesion in a coronary artery with a reference vessel diameter (RVD) <2.8 mm between March 1999 and March 2001. Sixty balloon expandable tubular stents were implanted in 57 lesions (29 Type B2/C, mean RVD: 2.54 +/- 0.16 mm) without intravascular ultrasound guidance under a heparin-aspirin-ticlopidine regimen. The mean diameter stenosis (DS) decreased from 75.8 +/- 13.6% to 4.2 +/- 1.9% (P<0.0001) with stenting at a mean deployment pressure of 13.6 +/- 1.7 atm and a final balloon to RVD ratio (FB/RVD) of 1.08 +/- 0.03. All stents were deployed successfully. Acute stent thrombosis occurred in 3 patients (6%), one died, and 2 developed non-Q-wave myocardial infarction (procedural success 94%). Clinical follow-up, available in 48 patients, revealed a 29% target lesion revascularization rate, a 2% myocardial infarction rate, and a 71% event-free survival at a mean of 11.6 months. Angiographic follow-up, available in 40 patients, showed a DS of 48.8 +/- 31.3% and a binary restenosis rate of 50% at a mean of 7.7 months. The FB/RVD ratio was significantly lower in the group with restenosis than in the group without (1.06 +/- 0.02 vs 1.1 +/- 0.05, P = 0.04). Subgroup analysis yielded a significantly greater rate of restenosis in diabetics with complex (Type B2/C) lesion morphology compared to nondiabetics with simple (Type A/B1) lesions (75% vs 21%, P < 0.05). In conclusion, stenting in vessels <2.8 mm was found to be associated with a high rate of acute stent thrombosis and in-stent restenosis. Further analysis detected a subgroup of patients without diabetes or complex lesions who could be stented with an acceptable in-stent restenosis rate.

Head-to-head comparison of two different low-molecular-weight heparins in acute coronary syndrome: a single center experience.

Low-molecular-weight heparins (LMWH) of different types have yielded different results when used in the setting of unstable angina (UA) or non Q-wave myocardial infarction (NQMI). We compared the safety and therapeutic efficacy of two different LMWHs, namely dalteparin (Dalt.) and enoxaparin (Enox.), in the acute phase (first 5 days) of UA or NQMI. One hundred and forty-two patients with UA/NQMI were randomly assigned to treatment with either Dalt. [120 IU/kg twice daily by subcutaneous (SC) injection] or Enox. [1 mg/kg twice daily by SC injection]. The occurrence of any one of death, myocardial infarction, or angina recurrence within 5 days of the first LMWH injection was the endpoint of the study. There were 69 patients in the Enox. group (53 males, 16 females, mean age: 60.3+/-11.9) and 73 patients in the Dalt. group (54 males, 19 females, mean age: 59.6 +/-10.3). The baseline characteristics of the patients in the two groups were similar. There were no deaths in either group. Myocardial infarction occurred in two patients in the Dalt. group (4%). Angina recurrence was seen in 11 patients in the Enox. group (16%) and in 11 patients in the Dalt. group (15%). Overall, any of the events that made up the endpoint occurred in 11 (16%) and 14 (19%) patients in the Enox. and Dalt. groups, respectively (P>0.05). The time to occurrence of the first event, however, was significantly longer in the Enox. group (82.3+/-33.2 versus 37.6+/-23.4 hours, P=0.007). Thrombocytopenia and allergic reactions were not detected in any patient. Major bleeding was seen in I patient in the Enox. group. Minor bleeding occurred in 17 (25%) and 21 (29%) patients in the Enox. and Dalt. groups, respectively (P>0.05). Enoxaparin and dalteparin were found to be equally safe and effective for the early management of UA/NQMI, but enoxaparin appeared to delay the occurrence of MI or angina recurrence as compared to dalteparin in this setting.

Medium-term follow-up of intermediate coronary stenoses left unrevascularized based on myocardial fractional flow reserve findings.

OBJECTIVE: Coronary stenoses of intermediate severity create difficulties in decision making when revascularization is concerned. Myocardial fractional flow reserve (mFFR), an accurate tool to identify physiological significance of individual coronary stenoses, may help solve this problem. METHODS AND RESULTS: Fifty-eight intermediate (30-70%) coronary stenoses in 51 patients (mean age 54.4 +/- 8.9 years, 9 women) were left unrevascularized because of normal (> or = 0.75) mFFR findings and the patients were prospectively followed with regard to the occurrence of death, myocardial infarction and target vessel revascularization. The mean reference vessel diameter, percent stenosis and mFFR of the intermediate lesions were 3.3 +/- 0.3 mm, 46.8 +/- 9.2% and 0.86 +/- 0.05, respectively. Of the 58 intermediate lesions, 20 (34%) were associated with perfusion defects on thallium scan. Significant (> 70%) disease in addition to the one with the intermediate stenosis was present in I coronary artery in 24 (47%), and 2 coronary arteries in 6 (12%) patients and angioplasty of at least one significant stenosis was performed at the initial evaluation in 18 (35%) patients. Follow-up for a mean of 16.6 +/- 6.6 months disclosed no death or myocardial infarction. Target vessel revascularization was performed in 3 (6%) patients at a mean of 4 +/- 2.6 months. A control angiogram, which was performed in 12 of 18 patients who had undergone angioplasty at the initial evaluation revealed restenosis in 3 (25%) patients with no significant angiographic changes in the target intermediate stenoses. Anginal status was found to be significantly improved at follow-up. CONCLUSIONS: In this study, we found that intermediate coronary stenoses with an mFFR > or = 0.75 have a favourable medium-term clinical outcome with respect to major cardiac adverse events when left unrevascularized based on mFFR findings.

Frequency of cardiac troponin-t elevation after successful direct stenting.

Direct stenting (stenting without balloon predilation) is a novel approach in percutaneous treatment of coronary artery lesions. This approach may also significantly lower the rate of procedural ischaemic complications by reducing aggression to the vessel wall and immediately sealing the dissections created due to balloon inflation by the endoprosthesis. However, the incidence of minor myocardial infarction after direct stenting is unknown. The purpose of this study was to measure cTnT, creatine kinase and its isoform, CK-MB after apparently successful elective stent implantation without balloon predilation. Enzyme levels were measured just before and 16 hours after the procedures. A second-generation commercial ELISA cTnT assay (Boehringer Mannheim Corporation) was used to measure cTnT with a cutoff of 0.1 ng/dl. There was no abnormality in all three enzymes before the procedure. CTnT was elevated in 6 patients (13.6%), CK and CK-MB were elevated in 1 (2.3%) patient at 16 hours after the procedure. Both CK and CK-MB elevation were observed in the patient with side branch occlusion. In all others cTnT measurements in addition to CK-MB measurements are needed to detect this minor myocardial damage. To the best of our knowledge this is the first report evaluating the incidence of myocardial injury after direct stenting. Direct stenting by avoiding balloon-induced complications may decrease procedural myocardial necrosis. Randomized studies with larger patient populations should be conducted to compare this approach with conventional stenting. CTnT measurements in addition to CKMB measurements are essential in detecting this minor myocardial damage.

Sidebranch occlusion after coronary stenting with or without balloon predilation: direct versus conventional stenting.

Direct stenting (DS) is a novel approach in percutaneous treatment of coronary artery lesions. Several studies confirmed the safety and feasibility of the procedure with success rates greater than 90%. However, the data regarding the incidence of sidebranch occlusion (SBO) after DS are scarce. The purpose of this study was to evaluate SBO (> 1 mm) after DS and compare it to conventional stenting (CS) with balloon predilation. The study population consisted of 151 patients (88 underwent DS, 63 underwent CS) with 185 sidebranches jailed by the stent (110 in DS group, 75 in CS group). SBO was observed in 20 out of 110 patients in the DS group (18.2%) and 18 out of 75 patients in the CS group (24%). Although the incidence of SBO was higher in the CS group compared to the DS group (24% vs. 18.2%, respectively), these values did not reach statistical significance (p > 0.05). Most of the SBOs were observed in cases with type D sidebranch morphology (p < 0.001) and in cases with sidebranch ostial diameter stenosis 50% (p = 0.019). None of the other clinical and angiographic variables predicted the SBO. To the best of our knowledge, this is the first report comparing incidence of SBO between two different PCI methods (CS vs DS). Randomized studies with larger patient populations should be conducted to compare this approach with conventional stenting.

Recanalization of an occluded major side branch after stenting with intracoronary adenosine.

Adenosine is a powerful direct coronary vasodilator with a very short half-life that has been shown to be effective in avoiding and reversing no reflow. We report an immediate successful recanalization of an occluded major side branch after stenting with acute intracoronary adenosine administration. The beneficial effect of adenosine may imply that the side branch occlusion (SBO) in this case could be due to spasm or distal embolization of the atherosclerotic debris ending up with no flow. We believe that adenosine could be helpful in at least some cases of SBO and therefore may be worth attempting.

Conventional versus direct stenting in AMI: effect on immediate coronary blood flow.

There are no data regarding the potential benefits of direct stenting in the setting of AMI. The aim of this study was to evaluate the impact of direct stenting on the angiographic results and compare it to conventional stenting performed in the setting of AMI. We reviewed our institutional interventional database and identified 44 patients who had undergone stenting in the setting of AMI (29 primary and 15 rescue angioplasty). Patients were then divided into two groups; group A consisted of patients who had undergone conventional stenting (23 patients) and group B those who had undergone direct stenting (21 patients). Angiographic success was defined as TIMI flow grade 2. The baseline TIMI 0-1 flow was higher in group A compared to group B (74% vs. 24%; p < 0.05). TIMI flow rates before stenting (after balloon predilation in group A and after guidewire crossing in group B) and angiographic success (TIMI flow 2) after stenting were similar in both groups (p > 0.05). However, the final TIMI 3 flow were significantly better in group B after stenting (65% vs. 95%; p < 0.05). Although there was no no re-flow in group B, three patients in group A had no re-flow after balloon predilatation of lesions with baseline TIMI 2 flow. There was a statistical tendency to a higher TIMI 3 flow in patients treated with direct stenting in the setting of AMI. Direct stenting strategy in thrombus containing lesions seems to be a safe and feasible approach in avoiding no re-flow.

Effects of left ventricular systolic dysfunction on left atrial appendage and left atrial functions in patients with chronic nonvalvular atrial fibrillation.

OBJECTIVE: It has been claimed that left ventricular (LV) systolic dysfunction impairs left atrial (LA) and left atrial appendage (LAA) functions. In this study, we compared the LA and LAA function parameters in patients with chronic nonvalvular atrial fibrillation (AF) with and without LV systolic dysfunction. METHODS AND RESULTS: The study population consisted of 28 patients with chronic nonvalvularAF. Group I consisted of 12 patients with LV systolic dysfunction (mean age: 61 +/- 14 years; LV ejection fraction: 44 +/- 6%), group II of 16 patients with normal LV systolic function (mean age: 52 +/- 15 years; LV ejection fraction: 65 +/- 3%). LV ejection fraction (EF) was measured by echocardiography utilizing bi-plane area length method. The following LA and LAA transoesophageal echocardiography parameters were obtained: I) LA diameter, 2) LAA ejection velocity, 3) LAA filling velocity, 4) LAA ejection fraction, 5) pulmonary venous (PV) systolic velocity, 6) PV diastolic velocity, 7) PV systolic velocity/diastolic velocity ratio. The left atrium diameter was significantly larger in group I than in group 11 (4.7 +/- 0.7 cm vs. 3.8 +/- 0.6 cm, p < 0.05). The LAA ejection velocity and LAA ejection fraction were significantly lower in group I than in group 11 (22.6 +/- 15.5 cm/s vs 37.5 +/- 11.3 cm/s and 26.9 +/- 20.8% vs. 41.3 +/- 10.9%, p < 0.05 for both comparisons). The PV systolic velocity and PV systolic velocity/diastolic velocity ratio were significantly smaller in group I than in group II (26.2 +/- 14.8 cm/s vs. 51.5 +/- 22 cm/s and 0.7 +/- 0.6 vs. 1.2 +/- 0.5, p < 0.05 for both comparisons). Although decreased LAA filling and PV diastolic velocities were determined in group I, no significant difference existed between groups I and II. Thrombus and/or spontaneous echo contrast (SEC) in the LA and/or LAA were more frequent in group I (75% vs. 18%, p < 0.05). CONCLUSION: These results indicate that LV systolic dysfunction impairs various LA and LA function parameters and is associated with an increased frequency of SEC and/or LA thrombus in patients with chronic nonvalvularAF.

Myocardial injury after apparently successful coronary stenting with or without balloon dilation: direct versus conventional stenting.

Direct stenting (i.e., stenting without balloon predilation) is a novel approach to the percutaneous treatment of coronary artery lesions. This approach, by reducing aggression to the vessel wall and immediately sealing the dissections created by balloon inflation by the endoprosthesis, may also significantly lower the rate of procedural ischemic complications. Our purpose was to measure cardiac troponin T (cTnT), creatine kinase and its isoform CKMB after apparently successful elective stent implantation with conventional stenting (CS) or direct stenting (DS) and to compare the procedural myocardial injury between these 2 approaches. Enzyme levels were measured before and 16 hours post-procedure. A second-generation commercial ELISA cTnT assay (Boehringer Mannheim Corporation) was used to measure cTnT with a cut-off of 0.1 ng/dl. There was no abnormality in any of the 3 enzymes in either group before the procedure. Although the incidence of cTnT was elevated in 4 of 37 patients (10.8%) in the DS group and in 5 out of 23 patients (21.7%) in the CS group at 16 hours post-procedure, these values did not reach statistical significance (p > 0.05). Creatine kinase and CKMB levels were not elevated in any of the patients. CTnT and CKMB measurements are needed to detect this minor myocardial damage. Randomized studies with larger patient populations should be conducted to compare the two different approaches.