An assessment of the quality of optical coherence tomography image acquisition.

Optical coherence tomography (OCT) provides excellent image resolution, however OCT optimal acquisition is essential but could be challenging owing to several factors. We sought to assess the quality of OCT pullbacks and identify the causes of suboptimal image acquisition. We evaluated 784 (404 pre-PCI; 380 post-PCI) coronary pullbacks from an anonymized OCT database from our Cardiovascular Imaging Core Laboratory. Imaging of the region-of-interest (ROI-lesion or stented segment plus references) was incomplete in 16.1% pullbacks, caused by pullback starting too proximal (63.7%), inappropriate pullback length (17.1%) and pullback starting too distal (11.4%). The quality of image acquisition was excellent in 36.3% pullbacks; whereas 4% pullbacks were unanalyzable. Pullback quality was most commonly affected by poor blood displacement from inadequate contrast volume (27.4%) or flow (25.6%), followed by artifacts (24.1%). Acquisition mode was 'High-Resolution' (54 mm) in 74.4% and 'Survey' (75 mm) in 25.6% of cases. The 54 mm mode was associated with incomplete ROI imaging (p = 0.020) and inadequate contrast volume (p = 0.035). We observed a substantial frequency of suboptimal image acquisition and identified its causes, most of which can be addressed with minor modifications during the procedure, ultimately improving patient outcomes.

Feasibility of coronary angiogram-derived vessel fractional flow reserve in the setting of standard of care percutaneous coronary intervention and its correlation with invasive FFR.

BACKGROUND: Vessel Fractional Flow Reserve (vFFR), a new angiography-derived method for the functional assessment of coronaries, was recently shown to have good correlation with invasive wire-derived FFR, when vFFR-specific image acquisition requirements were followed. We sought to investigate the feasibility of vFFR analysis and its correlation with FFR in the situation where angiography is completed in routine fashion, without intention for virtual analysis. METHODS: Utilizing an anonymized database maintained at our Cardiovascular Imaging Core Laboratory, we included angiographic images from patients that underwent pre- and post-PCI FFR. CAAS Workstation 8.1 software (Pie Medical Imaging) was used for vFFR evaluation. RESULTS: Out of 624 angiograms (312 pre-PCI and 312 post-PCI), vFFR was successfully analyzed in 219 (35.1%) (115 pre-PCI and 104 post-PCI). Reasons for vFFR analysis failure were: <2 angiographic projections (42.5%), table movement while acquisition (25.7%) and resolution incompatibility (15%). From 115 patients with analyzable pre-PCI vFFR, 74 (64.3%) showed agreement with the respective FFR results in terms of positive (≤0.80) vs negative (>0.80) FFR. Pearson's correlation coefficient between them was 0.449 (p < 0.0001). From 104 lesions with analyzable post-PCI vFFR, 94 had availability of FFR, 74 (78.7%) of which showed agreement between the vFFR and FFR. Pearson's correlation between the values was 0.115 (p = 0.2703). CONCLUSION: vFFR could be analyzed in about one-third of previously completed angiographies and a weak correlation was seen between vFFR and FFR. Our results show the importance of following the pre-specified requirements for vFFR analysis. Further studies are needed to validate the software in different settings.

Optical coherence tomography evaluation of the absorb bioresorbable scaffold performance for overlap versus non-overlap segments in patients with coronary chronic total occlusion: insight from the GHOST-CTO registry.

The Absorb bioresorbable vascular scaffold (BVS) promised to avoid some of the disadvantages of its metal predecessors. Even though it has been taken off the market, limited data is available about its use in coronary chronic total occlusion (CTO) and its performance in overlap segments, which would be of special research interest due to its large thickness. This data is still pertinent since the platform of bioresorbable devices has not been abandoned, with several companies working on it. We aimed to compare healing and performance between overlap (OL) and non-overlap regions (NOL) of CTO lesions treated with BVS, using optical coherence tomography (OCT). Fourteen patients with overlapping BVS were included from the GHOST-CTO registry, resulting in 25 OL and 38 NOL regions. OCT based parameters were compared between OL and NOL groups at baseline (post-implantation) and 12-month follow-up. The mean age was 61.7 ± 7.2 years and 12 (86%) were males. Twelve (86%) patients underwent PCI for stable coronary artery disease and 2 (14%) had unstable angina. At 12-month follow-up, mean lumen area decreased in both NOL and OL regions, but the decrease was significantly larger in the OL region (NOL - 0.7 ± 1.33 vs. OL - 2.4 ± 1.54 mm2; p = 0.002). Mean scaffold area increased in both regions, but increased significantly more in NOL ( + 1.1 ± 1.54 vs. + 0.4 ± 1.16 mm2; p = 0.016). The percent of uncovered struts was lower in the OL group (5.0 ± 6.6% vs. 3.75 ± 8.7%, p = 0.043), whereas the percentage of malapposed struts was similar (0.3 ± 0.5% vs. 0.7 ± 2.3%, p = 0.441). Neointimal hyperplasia (NIH) was more pronounced in the OL region (0.13 ± 0.04 vs. 0.24 ± 0.10 mm2, p = 0.001). The OL and NOL segments showed comparable healing in terms of coverage and malapposition. However, NIH was more prominent in OL region. The long-term clinical implications of these findings needs further evaluation. The present study provides important insights for future development of BVS technology.

Efficacy and safety of quinine loading dose in patients with severe falciparum malaria at a tertiary care hospital in Pakistan.

OBJECTIVE: To compare the clinical outcomes of a loading dose regimen of quinine with a uniform dose regimen in patients with severe falciparum malaria. METHODS: A retrospective chart review of 315 patients admitted with severe falciparum malaria and treated with quinine at a tertiary care teaching hospital of Karachi, Pakistan during 1999-2006 was conducted. Group A with 103 patients (32.7%) was given an initial loading dose of quinine while group B with 212 patients (67.3%) did not receive the loading dose. The two groups were compared in terms of reduction of parasite load, resolution of fever, recovery of consciousness and incidence of adverse effects. Outcome parameters were measured on the third day of therapy. RESULTS: More individuals in group A (62.1%) were afebrile as compared to group B (54.7%) at day 3 of therapy. Patients in group B showed greater reduction in parasitaemia (47.2% at baseline to 4.7% on day 3) as compared to group A (56.3 % at baseline to 9.7% on day 3). Following therapy, fewer patients in group B had altered consciousness (7.1% at baseline to 4.7% on day 3) as compared to patients in group A (7.8% at baseline to 5.8% on day 3). However, these associations were not statistically significant. The incidence of thrombocytopenia was higher in Group A (5.8%) as compared to Group B (0.9%). CONCLUSION: Although quinine loading dose may be more effective than uniform dose in rapid fever clearance; it also appears to be associated with higher toxicity. Uniform dose of quinine may be prescribed in severe falciparum malaria in view of its better safety profile.

Career goals of trainee physicians in internal medicine.

OBJECTIVE: To survey Internal Medicine trainees' future career choices and factors influencing their decision-making. DESIGN: Cross-sectional study. PLACE AND DURATION OF STUDY: The Aga Khan University Hospital, Karachi, from November 2006 to January 2007. SUBJECTS AND METHODS: A standard questionnaire was administered to the residents and Interns working in the Department of Internal Medicine of The Aga Khan University Hospital. The questionnaire covered demographic details, specialty choice, work-time distribution and factors influencing career choice. Descriptive statistics were applied. RESULTS: A total of 49 doctors participated with 57% females; and 43% males, having 33% interns and 67% residents. A minority (22%) opted for internal medicine, while 78% selected sub-specialties with cardiology (20%) being the most sought- after sub-specialty. Majority (69%) wanted to spend more time in clinical activities compared to administration (18%) or research (13%). Majority (92%) wanted to work in an academic setting. Availability of a structured training program (61%), ability to practice broad area of medicine (41%) and prestige of the specialty (41%) highly influenced their career choices. Forty one (82%) wanted to proceed abroad for further training and 80% wanted to eventually practice in Pakistan. CONCLUSION: Most of the interviewed under-training physicians wanted to pursue sub-specialty. Clinical work was more attractive compared to research. A structured training program was detrimental in affecting their choices. Majority wanted further training abroad but eventual settlement in Pakistan. The study results can help us create the basis for reforming the current training programs.

Syncope: experience at a tertiary care hospital in Karachi, Pakistan.

INTRODUCTION: Our aim was to determine the characteristics of patients presenting with syncope at a tertiary care hospital in Karachi, Pakistan. METHODS: A review of medical records was conducted retrospectively at the Department of Medicine, Aga Khan University Hospital, Karachi. Patients aged 16 and above, admitted from January 2000 to December 2005 with the diagnosis of syncope made by the attending physician were included. RESULTS: A total of 269 patients were included (75% males, mean age: 57.4 years). Neurogenic (vasovagal) syncope was the most common cause (47%), followed by cardiogenic syncope (18%) and orthostatic syncope (9%). A total of 24% were discharged undiagnosed. Twenty patients (7.4%) did not have any prodrome. Common prodromal symptoms included dizziness (61%), sweating (25%), palpitations (19%), nausea/vomiting (19%) and visual symptoms (17%). The distribution of symptoms according to cause of syncope revealed only breathlessness to be significantly associated with cardiogenic syncope (p = 0.002). Most patients with cardiogenic syncope were aged above 40 (98%, p < 0.001), had coronary artery disease (72%, p < 0.001) and abnormal electrocardiogram at presentation (92%, p < 0.001). CONCLUSION: Despite differences in burden of diseases, our findings were similar to those of published syncope literature. Further studies are needed to develop a protocol to expedite the evaluation and limit the work-up and admission in low-risk patients.