Kunadian Vijayalakshmi

Prospective, randomised, controlled trial to study the effect of intracoronary injection of verapamil and adenosine on coronary blood flow during percutaneous coronary intervention in patients with acute coronary syndromes

Objectives: To study the impact of injection of verapamil and adenosine in the coronary arteries on TIMI (Thrombolysis in Myocardial Infarction) frame count (TFC) after percutaneous coronary intervention (PCI) in patients with an acute coronary syndrome (ACS). Methods: Prospective, randomised, controlled study of the intracoronary administration of normal saline versus verapamil versus adenosine in patients undergoing PCI in the setting of an ACS, even when flow is visually established to be normal or near normal. Patients were randomised to receive verapamil (n  =  49), adenosine (n  =  51) or normal saline (n  =  50) after PCI. Quantitative angiography, TIMI flow grade (TFG), TFC and myocardial blush grade were assessed before PCI, after PCI and after drugs were given. Wall motion index (WMI) was measured at days 1 and 30. Results: 9 patients in the verapamil group developed transient heart block, not seen with adenosine (p ⩽ 0.001). Compared with saline, coronary flow measured by TFC improved significantly and WMI improved slightly but insignificantly in both the verapamil (TFC: p  =  0.02; mean difference in improvement in WMI: 0.09, 95% confidence interval (CI) 0.015 to 0.17, p  =  0.02) and the adenosine groups (TFC: p  =  0.002; mean difference in improvement in WMI: 0.08, 95% CI 0.004 to 0.16, p  =  0.04). The improvements in TFC and WMI did not differ significantly between the verapamil and the adenosine groups (TFC: p  =  0.2; mean difference in improvement in WMI: 0.01, 95% CI −0.055 to 0.08, p  =  0.7, respectively). Conclusion: Administration of verapamil or adenosine significantly improves coronary flow and WMI after PCI in the setting of an ACS. Flow and WMI did not differ significantly between verapamil and adenosine but verapamil was associated with the development of transient heart block.

Meta-analysis of randomized trials comparing anti-embolic devices with standard PCI for improving myocardial reperfusion in patients with acute myocardial infarction

Failure to achieve adequate myocardial reperfusion often occurs during PCI in patients with STEMI. This is in part due to atheromatous and thrombotic distal embolization. Several anti‐embolic devices have been developed to protect against distal embolization during percutaneous coronary interventions (PCI) to improve myocardial reperfusion and enhance event free survival. Evidence from current studies has not shown a consistent benefit, but anti‐embolic devices continue to be used.

Cardiac catheterisation: radiation doses and lifetime risk of malignancy.

Cardiac catheterisation and angiography uses ionising radiation and therefore produces a radiation dose to the patient and to the operating staff. The dose to the patient can be measured using thermoluminescent dosemeters placed on the skin or by using a large-area detector attached to the x ray tube to measure the dose–area product (DAP) for the incident x ray beam (DAP meter). The DAP is particularly useful for assessing and comparing the radiation dose from screening procedures. It provides a more useful indication of the overall patient exposure than measurement of surface dose at particular locations. The dose measurement is used either as a surrogate for radiation risk or as a step in actually estimating the risk. Published factors allow conversion of the DAP to effective dose, a derived quantity in which doses to different organs or tissues are weighted according to their radiosensitivity and summed to give a risk-related dose quantity.1–5 UK legislation does not give dose limits for patients undergoing medical diagnostic exposures, but requires adherence to the “as low as reasonably practicable” principle, and comparison of doses with diagnostic reference levels for common procedures. Published data for patient exposure, absorbed dose, effective dose and risk of malignancy from the different specific diagnostic cardiac catheterisation procedures are incomplete, and there are no national diagnostic reference levels for individual procedures. We undertook this study with the aim of establishing local patient doses for six different diagnostic cardiac catheterisation procedures …

Corrected TIMI frame count: applicability in modern digital catheter laboratories when different frame acquisition rates are used.

The original description of the TIMI frame count (TFC) method was based on angiograms acquired at 30 f/sec. Modern digital angiograms are acquired at lower frame rates (between 12.5 and 25 f/sec). Coronary angiography was acquired at 12.5 and 25 f/sec after 200 μg of intracoronary glyceryl trinitrate. Results of the corrected TIMI frame count (cTFC) at 12.5 and 25 f/sec for each vessel were: right coronary artery, 19.5 ± 5.2 and 20.4 ± 6.6 (P = 0.15); circumflex artery, 25.6 ± 8.2 and 25.9 ± 8.7 (P = 0.5); and left anterior descending artery, 22.5 ± 8.1 and 23.8 ± 10.4 (P = 0.15), respectively. The mean difference in the TFC between two injections by the same operator and by two operators was 0.4 (P = 0.7) and 0.4 (P = 0.2), respectively. The mean difference in the TFC for repeat measurements by the same observer and between two observers was 0.26 (P = 0.3) and 0.06 (P = 0.8), respectively. We confirm that the cTFC is a quantitative method to assess coronary flow that can be applied in a modern digital laboratory. Catheter Cardiovasc Interv 2004;63:426–432.

Strain rate imaging pre- and post-percutaneous coronary intervention: a potential role in the objective detection of ischaemia in exercise stress echocardiography

AIMS To determine the feasibility of strain rate imaging (SRI) in the objective detection of exercise-induced ischaemia. METHODS AND RESULTS Sixteen patients undergoing elective percutaneous coronary intervention (PCI) underwent treadmill exercise stress echocardiography (ESE) pre- and post-PCI. Measurement of systolic SRI parameters was attempted in all myocardial segments at baseline, peak stress, and in recovery. Segments were divided into those supplied by target (Group 1) and non-target vessels (Group 2). Percutaneous coronary intervention was successful in all patients. In Group 1, there was no significant difference in post-systolic strain rate (SRps) at baseline or at peak stress but there was significantly greater SRps pre-PCI compared with post-PCI at 30 min into recovery (-0.37 +/- 0.53 vs. -0.07 +/- 0.44 s(-1), P = 0.004). There were similar findings with the SRps index [ratio of SRps:peak systolic strain rate (SRsys)]. Group 2 segments did not demonstrate any significant differences in SRI parameters pre- and post-PCI. At peak exercise pre-PCI, Group 1 segments had significantly delayed time to SRsys compared with Group 2 (0.12 +/- 0.05 vs. 0.09 +/- 0.05 s, P = 0.013), a difference that was abolished post-PCI. CONCLUSION This suggests a potential role for SRI in the objective detection of exercise-induced ischaemia by echocardiography at peak stress and during recovery at the time of improved image quality.

Impact of catheter sizes and intracoronary glyceryl trinitrate on the TIMI frame count when digital angiograms are acquired at lower frame rates during elective angiography and PCI

The TIMI frame count (TFC) is a useful measure of coronary flow. To be widely applicable, the effect of different catheter sizes and the use of intracoronary glyceryl trinitrate (ICGTN) must be determined when films are acquired at lower acquisition rates (12.5 frames/s, f/s). Methods: We compared 6F versus 5F diagnostic catheters (n = 44), 6F versus 7F diagnostic catheters (n = 45) and 6F diagnostic versus 7F guide catheters (n = 44). In the nitrate angiography group (n = 141), coronary angiography was performed before and after 200 micrograms of ICGTN. In the nitrate percutaneous coronary intervention (PCI) group (n = 48), coronary angiography was performed before and after 200 micrograms of ICGTN after the completion of the elective PCI procedure. Results: The mean difference in the uncorrected TFC using 6F and 5F was 0.02 (95 % CI −0.5, 0.6; P = 0.9); using 6F and 7F diagnostic catheters it was 0.3 (95% CI −0.49, 1.1; p = 0.4); and using 6F diagnostic and 7F guide catheters it was 0.4 (95% CI −2.6, 3.4; P = 0.7) respectively. In the nitrate angiography group, the uncorrected TFC before and after ICGTN was 13.1±6.2 and 15±7.5 (equivalent to 31.4±14.9 and 36±2 at 30 f/s), with a mean difference of 1.9 (95% CI 1.3, 2.5; P = <0.0001). In the nitrate PCI group, the uncorrected TFC before and after ICGTN administration was 9.2±3.7 and 10.3±4.2 (equivalent to 22.6±9.6 and 25.2±11 at 30 f/s) respectively with a mean difference between the two injections of 1.2 (95% CI −0.4, 1.9; P = 0.003). Conclusion: We have demonstrated that the catheter sizes did not significantly affect the TFC when angiography was performed at 12.5f/s. The use of ICGTN significantly increased the TFC in both normal and diseased coronary arteries. This effect was also observed when ICGTN was administered into the culprit vessels after the completion of the elective PCI procedure. This effect must be considered when investigating the impact of specific treatments or drugs on coronary flow.

Rescue angioplasty after failed fibrinolysis foracute myocardial infarction: Predictors of a failed procedure and 1-year mortality

Rescue angioplasty (rPCI) for failed fibrinolysis is associated with a low mortality if successful, but a high mortality if it fails. The latter may reflect a high‐risk group or harm in some patients. Predictors of success or failure of rPCI may aid selection of patients to be treated.

The impact of chronically diseased coronary arteries and stenting on the corrected TIMI frame count in elective coronary angiography and percutaneous coronary intervention procedures.

The impact of chronic coronary obstructions on resting blood flow in stable cardiac patients and the response to percutaneous coronary intervention (PCI) using the TIMI frame count method has not been well documented. We studied the impact of coronary artery stenosis severity on the corrected TIMI frame count (cTFC) in chronically stenosed coronary arteries. We prospectively and quantitatively determined the impact of stenting on the cTFC during elective PCI. Methods: In substudy 1, analysis was performed to obtain the mean cTFC for arteries with <50% stenosis (Group A), 51–75% stenosis (Group B), 76–85% stenosis (Group C1), 86–95% stenosis (Group C2) and 96–99% stenosis (Group C3). In substudy 2, the cTFC and quantitative coronary angiography were performed pre‐ and post‐PCI. Results: In substudy 1, the cTFC increased exponentially beyond a diameter stenosis of 75% (P < 0.01). However there was no significant difference in the cTFC for coronary arteries with <75% stenosis. In substudy 2, the overall pre‐ and poststenting cTFC was 17.1 ± 11.7 and 7.8 ± 2.7 (P < 0.01) and the TFC index [calculated by dividing the mean cTFC for the relevant artery by the mean cTFC for the corresponding coronary artery in a previously derived control group in our laboratory] was 1.6 ± 1 and 0.7 ± 0.2 (P = < 0.01), respectively. Conclusion: We have demonstrated that there was a significant increase in the cTFC when the coronary artery stenosis was more than 75% reflecting significant flow abnormalities at this degree of stenosis in chronically diseased coronary arteries. Following stenting there is a significant improvement in the cTFC, which is better than the cTFC for arteries with normal flow, suggesting early hyperaemia.

Angiographic and physiologic assessment of coronary flow and myocardial perfusion in the cardiac catheterization laboratory

Introduction: For many years, coronary angiography has been used to define coronary artery lesions. Angiographic assessment of coronary flow using the TIMI flow grade system (TFG) and the TIMI frame count (TFC) methods have played a significant role in our understanding of coronary artery disease and they have proved useful in prediction of long-term clinical outcomes after myocardial infarction. The availability of invasive techniques to assess the physiological significance of coronary artery lesions allows a more rationale approach to the management of patients, particularly those with intermediate lesions. The TIMI scores and other angiographic parameters such as the TIMI myocardial perfusion grade (TMPG) are now integrated into clinical practice, as are the use of flow wires and pressure recording wires. Other angiographic techniques, (e.g. digital subtraction angiography), which at this time are predominantly research tools, will require software integration into the imaging chain to facilitate real-time analysis. Conclusion: In this article, we provide a comprehensive descriptive review of the different means of assessment of coronary flow in the cardiac catheterization laboratory, focusing on scores deducted from angiography as well as invasive haemodynamic measurements of blood flow and pressure.

Successful thrombus extraction with the Rescue™ thrombus management system during acute percutaneous coronary intervention improves flow but does not necessarily restore optimal myocardial tissue perfusion

We determined the effectiveness of the Rescue™ device in restoring flow and achieving optimal tissue perfusion during percutaneous coronary intervention (PCI) in thrombus‐laden coronary arteries. Methods: A total of 30 patients with an acute coronary syndrome underwent PCI using the Rescue device. Results: The mean age was 65.5 ± 9.8 years. Although the Rescue device could not be passed across the lesion in 6 (20%) cases, debris was aspirated in 26 (87%). The uncorrected TIMI frame count improved following the use of the Rescue device and improved further at the completion of PCI (92.2 ± 23.9 pre‐PCI vs. 38.7 ± 31.3 post‐Rescue vs. 21.96 ± 24 post‐PCI, P < 0.0001). The thrombus score improved from 4 ± 0 to 2.2 ± 1.29 to 0.86 ± 1.4 (P < 0.0001). TIMI flow grade (TFG) 3 was restored in 60% of cases following the Rescue device and in 87% after PCI. Myocardial blush grade 3 occurred in only 13% of patients following the Rescue device and 37% of patients after PCI. Conclusion: These data suggest that the Rescue device can aspirate considerable amounts of debris in the majority of patients and significantly improves the angiographic epicardial coronary blood flow. How effective such a device is in improving tissue perfusion and, thereby, clinical outcomes for patients remains to be seen.