Mark Pitney

Modifying fluoroscopic views reduces operator radiation exposure during coronary angioplasty

OBJECTIVES This three-part study examined the feasibility of reducing operator radiation exposure during coronary angioplasty. BACKGROUND As case loads and complexity increase, some cardiologists are receiving increasing radiation scatter doses. Techniques to reduce this are therefore becoming more important. METHODS First, the determinants of the operator dose were assessed by measuring the differences in scatter dose with different camera views. The relative contribution of fluoroscopy as opposed to cine was then quantified. Finally, operators were provided with these data, and subsequent changes in technique were evaluated. RESULTS Left anterior oblique views resulted in 2.6 to 6.1 times the operator dose of equivalently angled right anterior oblique views. Increasing steepness of the left anterior oblique view also resulted in a progressive increase in operator dose, with left anterior oblique 90 degrees causing eight times the dose of left anterior oblique 30 degrees and three times that of left anterior oblique 60 degrees. In the 45 coronary angioplasty cases prospectively analyzed, fluoroscopy was found to be a greater source of total radiation than cine by a 6.3:1 ratio (range 1.1 to 15.8). Once operators were made aware of the importance of left anterior oblique fluoroscopy, there was a marked reduction in its use. When this was not feasible, there was a reduction in the steepness of the angulation. Left anterior oblique fluoroscopy during angioplasty of the left anterior descending and circumflex coronary arteries was reduced from 40% of total screening time to approximately 5%, and left anterior oblique angulation for fluoroscopy during angioplasty of the right coronary artery decreased from 43.6 degrees (+/- 9.1 degrees) to 29.4 degrees (+/- 2.2 degrees). Success rates (90% vs. 89%) and screening times (19.5 vs. 20.7 min) remained unchanged in 200 coronary angioplasties performed after the study. Average operator radiation dose (measured by radiation badges worn under lead at waist level) was reduced from 32.6 to 14.3 microSv/operator per week despite a slight increase in case load. CONCLUSIONS Fluoroscopy is the major source of total radiation exposure during coronary angioplasty, with left anterior oblique views providing the highest dose. Modification of views is feasible and will result in significant reduction of operator radiation dose.

Disassembly of a rotablator: getting out of a trap.

The rotablator burr rarely becomes trapped within calcified lesions. Manual traction can be ineffective and dangerous. We report a case that illustrates a novel technique involving use of a percutaneous snare in conjunction with partial disassembly of the rotablator device to remove a trapped burr without need for open surgical intervention. Cathet Cardiovasc Intervent 2003;59:463–465.

Everolimus-eluting Bioresorbable Vascular Scaffold Implantation in Real World and Complex Coronary Disease: Procedural and 30-day Outcomes at Two Australian Centres

BACKGROUND The Absorb BVS is a new generation of coronary stent designed to provide coronary arteries with mechanical support of a temporary nature, following balloon angioplasty. Clinical trials of the device have shown promising results thus far, however concern surrounds the deliverability of the device in real-world and complex coronary disease, and the possible higher incidence of early scaffold thrombosis when compared to conventional metallic drug-eluting stents. METHODS Implantation of the Absorb BVS was attempted in 152 lesions in 100 patients at two Sydney teaching hospitals, as part of a prospective registry. Lesions treated reflected a wide spectrum of real-world disease. Young patient age, long lesion length and involvement of the mid-portion of the left anterior descending artery were the strongest factors likely to influence the decision to use the Absorb BVS over conventional metallic stents. There were no restrictions on the lesion length, or on the number of lesions or vessels treated. Type C lesions made up 37% of all lesions treated with 64% of these being long lesions (>20mm). The Absorb BVS was successfully implanted in 98.8% of cases. Post-dilatation was performed in 95% of scaffolds. Peri-procedural non-ST elevation myocardial infarction occurred in four cases. Scaffold thrombosis did not occur in any patient at 30 days follow-up. There was no death, or need for target lesion revascularisation in-hospital or at 30 days. CONCLUSIONS High rates of procedural success were achieved with minimal complications with use of the Absorb BVS in real-world coronary disease, including complex disease. These results suggest that the reduced deliverability of the device can be largely overcome by meticulous lesion preparation, and that early scaffold thrombosis may be minimised through scaffold post-dilatation.

Activated clotting time differential is a superior method of monitoring anticoagulation following coronary angioplasty

The standard high-range activated clotting time (sHR ACT) is used to monitor anticoagulation postangioplasty (PTCA), but may be unreliable. We assessed the accuracy of a new method we termed the ACT differential (ACT Diff), obtained by measuring the difference between an sHR ACT and a heparinase ACT from the same sample. Heparinase removes heparin from its sample and provides a current heparin-free baseline. For phase 1 of the study, the sHR ACT, ACT Diff, and laboratory APTT were measured in 250 samples from 75 PTCA patients. In 125 samples with an APTT prolonged but within measurement range, linear regression against the APTT was performed. The correlation coefficient was 0.74 for the ACT Diff and 0.24 for the sHR ACT. An ACT Diff of 15-25 sec was found to equal an APTT of 2.5-3.5 x control. In 50 samples with a normal activated partial thromboplastin time (APT), there was good differentiation by the ACT Diff of results from those adequately heparinized, with a value of 0.9 +/- 4.4 sec. The sHR ACT was 114 +/- 15.5 sec, and could not reliably distinguish between anticoagulated and nonanticoagulated samples. In 75 samples obtained with a high APTT (above measurement range), the ACT Diff was > 30 sec in 95% of samples, and again this allowed differentiation from therapeutic samples. The equivalent sHR ACT was 148 sec, and could not reliably distinguish between anticoagulated and overanticoagulated samples as the ACT Diff could. In phase 2, to examine the clinical usefulness of the ACT Diff, 286 patients were managed post-PTCA by starting heparin when ACT Diff fell to < 50 sec, maintaining ACT Diff at 15-25 sec during heparin infusions, and following cessation of heparin, by removing sheaths when the ACT Diff was < 7 sec. These patients were compared to a control group of 250 patients. Major bleeding (5% vs. 0.5%, P < 0.005) and minor bleeding (30% vs. 13%, P < 0.001) were significantly reduced in the group managed using the ACT Diff. The reduction in bleeding was thought to be due to the rapid availability of reliable results. Abrupt closure was low in both groups (0% with ACT Diff vs. 0.8%). No other thrombotic events occurred. Following phases 1 and 2, the ACT Diff replaced the APTT in all PTCA patients at this institution. In the 18 mo from July 1993, 1,104 patients were managed this way. Incidence of major bleeding (0.2%), transfusion requirement (0.1%), false anneurysm (0.6%), and abrupt closure during heparin infusion (0.1%) remained low. In conclusion, the ACT Diff is more accurate than an sHR ACT, and its clinical use in PTCA patients is associated with a very low incidence of complications from anticoagulation. Its routine use should be considered by units unable to obtain rapid APTT results.

Intracoronary embolization and retrieval of radio-opaque ring marker on the ACS multi-link stent sheath

We report a case of intracoronary embolization of a ring marker on a stent sheath. The Microsnare device was unsuitable because of the distal position of the marker. After failing to retrieve the marker using an over-the-wire balloon and the two-wire technique, we succeeded in removing the marker using a balloon-on-wire system.

New bifurcation stenting technique: Shunt stenting

The optimal treatment of bifurcation lesions remains controversial. We describe a new technique we term shunt stenting. This technique incorporates both the new technology of drug‐eluting stents and a novel procedure for optimizing the ostial side branch stent positioning. To date, early angiographic and clinical follow‐up have been encouraging. Catheter Cardiovasc Interv 2004;63:474–481.

Impact of an aggressive coronary stenting strategy on the incidence of target lesion revascularization

Coronary stenting has been shown to reduce the incidence of target lesion revascularization (TLR) compared with balloon angioplasty in highly selected patients. However, the impact of an aggressive coronary stenting strategy in unselected patients on the overall incidence of TLR is unclear. We assessed the effect of increased stenting by comparing long-term results in consecutive patients who underwent successful percutaneous revascularization (with or without stents) during June to December 1995 (n=347) with those in June to December 1996 (n=401). Stents were used in 22.5% of patients in 1995 versus 66.1% in 1996 (p <0.0001). Mean age of the patients was 62+/-11 years (71% men) in 1995 versus 63+/-10 in 1996 (76% men) (p=NS). The 2 groups were well matched with the exception that the 1996 cohort included more patients with unstable coronary syndromes (25% in 1995 vs 34% in 1996 (p=0.003). There was no significant difference in the incidence of in-hospital adverse events. After 12 months of follow-up (complete in 95% of patients in each group), the incidence of TLR was significantly lower in the 1996 cohort than in the 1995 cohort (8.5% vs 14.7%, p=0.0075). This was mainly due to reduced requirement for repeat angioplasty in 1996 patients compared with 1995 (6.5% vs 11.8%, p=0.011). It is concluded that in an unselected patient population, an aggressive coronary stenting strategy was associated with a marked overall reduction in requirement for TLR over a 12-month period.

Simultaneous use of a diagnostic catheter to facilitate stent deployment in aorto-ostial artery stenosis: a case report.

Correct positioning of a stent at an ostial lesion can be difficult due to poor visualisation once the guide is backed out of the artery to allow deployment. This case report illustrates a technique whereby the simultaneous use of a diagnostic catheter allows optimal visualisation of stent position, whilst maintaining a stable guide position well away from the stent.

Balloon Aortic Valvuloplasty in The Transcatheter Valve Era: Single Centre Indications And Early Safety Data in A High Risk Population

BACKGROUND The introduction of transcatheter aortic valve implantation (TAVI) has generated a renewed interest in the techniques available to treat high-risk patients with severe aortic stenosis (AS). We report our single centre experience with balloon aortic valvuloplasty (BAV) focussing on indications, procedural success and 30-day outcomes. METHODS We retrospectively reviewed all patients that underwent BAV procedures at our institution between August 2012 and August 2014. Procedural success and complications were adjudicated according to VARC-2 criteria. RESULTS Fifty-one consecutive adult patients with severe symptomatic AS underwent a total of 55 BAV procedures. The patients had a mean age of 88±5.7 years and all had extensive comorbidities with a high surgical risk (mean logistic EuroSCORE of 25.22%±14.5%). Indications for BAV included palliation of symptoms n=42 (76%); bridge to definitive valve replacement (n=6, 11%); and evaluation of response (n=6, 11%). The procedure was completed in all patients with no intraprocedural deaths (within 24hours) and low 30-day mortality at 3.9% (n=2). Minor vascular complications occurred in 11.8% (n=6), whilst permanent pacemaker implantation was required in 5.8% (n=3). There were no cases of myocardial infarction, stroke, tamponade, severe aortic regurgitation or major vascular complications during 30-day follow-up. CONCLUSIONS Balloon aortic valvuloplasty may be performed safely and effectively with high procedural success and low 30-day complications, even in a very high-risk and elderly cohort of patients in whom the role of TAVI is uncertain or inappropriate.

PT187 Bioresorbable scaffolds in the treatment of chronic total occlusions (CTO)

Introduction: There is convincing evidence on the usefulness of manual thrombectomy in management of ST-elevation myocardial infarction. Experimental data obtained in vitro disclosed important differences in physicomechanical parameters required for effective thrombus aspiration with distinct aspiration catheters (AC). Direct in vitro comparison of several commercially available AC showed substantial differences in their trackability, pushability, and most of all, different volume of standardized saline solution or thrombus aspirated within a prespecified time unit. Objectives: The aim of the study was to assess the impact of different manual AC on immediate angioplasty results. For this purpose we have performed a stratified metaanalysis of randomized trials and reviewed the articles under several efficacy categories. Methods: From Medline and Cochrane Library we have idenified 11 randomized controlled trials with six different manual AC: Diver CE, Export, Eliminate, Pronto, Rescue, and Thrombuster. Results: Macroscopic thrombus was removed in 98.5% of cases in Eliminate group; 91% of cases in Diver CE group, 89% of cases in Pronto and Rescue groups, and 75.9% of patients in Export group. The use of thromboaspiration is better in achieving final TIMI III flow in comparison to PCI alone (OR 1.59 with 95% CI 1.16 – 2.19, p 1⁄40.004), however none of the aspiration catheter proved to be better than the others. The use of thromboaspiration is better in achieving final myocardial blush grade 3 in comparison to PCI alone (OR 1.94 with 95% CI 1.57 – 2.39, p 1⁄40.000) with best performance of Pronto (OR 9.48, p1⁄40,000), Diver (OR 2.57, p1⁄40.0058), Thrombuster (OR 2.33, p1⁄40.04), and Export (OR 1.77, p 1⁄40.000). The only aspiration catheter to prevent distal embolization is Pronto (OR 0.24, 95% CI 0.08 – 0.78, p1⁄40.0178). Thromboaspiration is better in achieving complete resolution of ST elevation in comparison to PCI alone (OR 1.42 with 95% CI 1.06 – 1.9, p 1⁄40.0179) and the only catheter to impact the complete ST resolution is Pronto (OR 2.08 with 95% CI 1.07-4.06, p1⁄40.031). Conclusion: This stratified metaanalysis shows Pronto aspiration catheter as most efficacious in restoring epicardial blood flow and myocardial perfusion in culprit vessel. However we must be cautious in interpreting this data as they are based on a single trial with Pronto aspiration catheter. The results of this metaanalysis are meant to be helpful in choosing the best aspiration catheter for everyday practice in STEMI patients. Disclosure of Interest: None Declared