Amjid Iqbal

Serum lipid levels in relation to serum thyroid‐stimulating hormone and the effect of thyroxine treatment on serum lipid levels in subjects with subclinical hypothyroidism: the Tromsø Study

Objective.  To evaluate the relation between serum thyroid‐stimulating hormone (TSH) and lipids.

Blood pressure in relation to serum thyrotropin: the Tromsø study

It appears to be an association between hypothyroidism and hypertension. However, the relation between thyroid function and blood pressure within the normal serum thyrotropin (TSH) range is uncertain. In the fifth Tromsø study, which is a population-based health survey, serum TSH and blood pressure were measured. This gave us the opportunity to test the hypothesis of a relation between serum TSH and blood pressure within the normal serum TSH range. In all 5872 subjects (2623 male subjects) not using blood pressure or thyroxine medication were included in the present study. Within the normal serum TSH range (0.20–4.00 mIU/l), there was a significant and positive relation between serum TSH and both systolic and diastolic blood pressure. Within this range, and adjusted for age, body mass index and smoking status, the systolic blood pressure was 1.4 mm Hg and the diastolic 1.6 mm Hg higher in male subjects in the highest versus those in the lowest serum TSH quartile. The corresponding differences in the female subjects were 4.0 and 2.7 mm Hg, respectively. When dividing this cohort in those with systolic (>160 mm Hg) and diastolic (>95 mm Hg) hypertension, serum TSH was higher in the hypertensive subjects, but the differences were only statistically significant for diastolic hypertension (serum TSH 1.88±0.82 versus 1.69±0.74 mIU/l for male subjects, and 1.79±0.78 versus 1.63±0.75 mIU/l for female subjects, P<0.05). In conclusion, there is a modest, but significant positive association between serum TSH and blood pressure within the normal serum TSH range.

Persistent dysfunction of viable myocardium after revascularization in chronic ischaemic heart disease: implications for dobutamine stress echocardiography with longitudinal systolic strain and strain rate measurements

AIMS Studies of functional recovery after revascularization in chronic coronary artery disease are contradictory and mark a lack of knowledge of persistent dysfunction in the non-scarred myocardium. Based on tissue Doppler-derived regional longitudinal systolic strain and strain rate (SR), both at rest and during dobutamine stress (DS), we assessed to what extent ischaemia-related reduced myocardial function would recover after revascularization in hearts with predominantly viable myocardium. METHODS AND RESULTS Reference peak systolic strain and SR values were determined from tissue Doppler imaging in 15 healthy volunteers. Fifty-seven patients scheduled for coronary artery bypass grafting (CABG), with an average ejection fraction of 49%, underwent pre-operative magnetic resonance imaging (MRI) with late enhancement, resting echocardiography, and DS echocardiography (DSE), with assessment of systolic strain and SR and post-systolic strain (PSS). Eight to 10 months after CABG, myocardial function was reassessed. Forty per cent of all segments had reduced longitudinal systolic strain pre-operatively despite only 1.4% of segments with transmural infarctions on MRI. After revascularization, 38% of prior dysfunctional segments improved their resting strain, whereas 72% were improved by DS. Positive resting systolic strain indicated the absence of significant scar tissue. Resting systolic strain and DS strain responses were good prognosticators for functional improvement with areas under the receiver operating characteristic curve of 0.753 (0.646-0.860) and 0.790 (0.685-0.895), respectively. CONCLUSION Persistently reduced longitudinal function was observed in more than half of pre-operatively viable but dysfunctional segments after CABG. We propose that such a functional impairment marks a regional remodelling process not amendable to re-established blood flow.

Coronary bypass graft patency cannot be determined by multidetector spiral computed tomography

Objectives. Angiography by selective catheterization is the reference standard for coronary bypass graft patency assessment but carries a risk of serious complications. We have investigated whether 16-slice multidetector spiral computed tomography (MDCT) can substitute for selective angiography. Design. Two to three years after coronary artery bypass grafting, 45 patients with a total of 156 bypasses (100 single and 28 sequential grafts) were examined with both MDCT and conventional selective angiography on the same day. The bypasses were classified as patent, stenotic or occluded. Results. The likelihood ratio for MDCT-detected occlusion was 40, reflecting a fairly high combined sensitivity and specificity. However, 24% of the distal anastomoses could not be evaluated by MDCT, mainly because of respiratory movements, artifacts due to metal clips, and small vessel dimensions. Moreover, seven out of 117 bypasses (6%) deemed evaluable by MDCT were wrongly classified by this method. Conclusions. At present, 16-slice MDCT cannot replace selective angiography for assessment of coronary bypass graft patency since 24% of bypasses could not be evaluated by this method, and an error rate of 6% is unacceptable.

Changes in Right Ventricular Shape and Deformation Following Coronary Artery Bypass Surgery—Insights from Echocardiography with Strain Rate and Magnetic Resonance Imaging

This study was designed to assess whether altered RV geometry and deformation parameters persisted well into the recovery period after presumably uncomplicated coronary artery bypass grafting (CABG). It was our hypothesis that the altered geometry of and load in the RV following pericardial opening would change both regional and global deformation indices for an extensive period postoperatively.

Left Ventricular Dysfunction in Subjects with Mild Secondary Hyperparathyroidism Detected with Pulsed Wave Tissue Doppler Echocardiography

Aims: To assess left ventricular function by conventional and pulsed wave tissue Doppler (PWTD) echocardiography in subjects with mild secondary hyperparathyroidism, and to evaluate whether PWTD would be more sensitive than conventional echocardiography in detecting subtle changes in LV systolic and diastolic function. Methods: In the fifth Tromsø study (2001) serum PTH and calcium were measured in 7,954 subjects. One hundred subjects with secondary hyperparathyroidism (SHPT; serum PTH >6.40 pmol/l and serum calcium <2.40 mmol/l) and 106 control subjects with normal PTH and calcium levels and with no history of cardiovascular disease were examined at the follow-up 6–12 months later. Results: Conventional transthoracic echocardiography and PWTD of mitral annulus were successfully performed in 83 cases and 88 controls. At follow-up mean serum PTH values were 6.0 ± 2.2 versus 3.2 ± 1.3 pmol/l (p < 0.05) and mean calcium 2.28 ± 0.10 versus 2.33 ± 0.08 mmol/l (p < 0.05) in cases and controls, respectively. Unpaired t test and multiple linear regression analyses were used. No significant differences in conventional echocardiographic parameters were found. However, PWTD showed reduced systolic velocity in septal, lateral and anterior mitral annulus (p < 0.05) and also reduced early diastolic velocity in septal and anterior mitral annulus (p < 0.05). Conclusion: Subjects with mild SHPT have impaired left ventricular long axis function as evaluated by PWTD compared to conventional echocardiography. PWTD seems to be a more sensitive tool in detecting minor changes in left ventricular function and the new modality should routinely be included in studies evaluating left ventricular function, especially the long axis function.

Radial artery graft patency relates to gender, diabetes mellitus and angiotensin inhibition

Abstract The radial artery is resistant to atherosclerotic degeneration and therefore appears more attractive for coronary artery bypass grafting than the saphenous vein. However, the patency of radial artery grafts varies widely among studies. Therefore, before deciding whether to adopt this as the conduit of choice second to internal mammary artery grafts, we have prospectively monitored our first cohort of patients with radial-to-coronary bypasses. Design. Angiographic and clinical outcome parameters were registered for the 119 patients receiving radial artery grafts at our institution during April 4, 2001 to October 7, 2003. Results. Reangiography of 102 patients (86%) showed that after two to three years, 79% of the radial artery and 87% of the saphenous vein grafts remained patent. Radial artery harvesting was well tolerated. Patency of radial artery grafts was correlated to diabetes mellitus (detrimental), gender (women had higher occlusion rates), and use of angiotensin inhibiting medication (beneficial). Conclusions. The pre-study assumption that radial artery grafts would out-perform those of saphenous vein at mid-term is not borne out. The propensity of radial artery graft failure in diabetics and the higher patency associated with angiotensin inhibition might both relate to endothelial modulation of the muscular tone of the graft.

Severe regional myocardial dysfunction by stress echocardiography does not predict the presence of transmural scarring in chronic coronary artery disease

AIMS Detection and correct localization of transmural lesions can be important for optimal treatment of patients with chronic coronary artery disease (CAD). The aim of the study was to investigate the ability of peak longitudinal ejection strain (PLS) to detect the presence and extent of scar-tissue in CAD patients with normal or near normal ejection fraction, in comparison to cardiac magnetic resonance (CMR). METHODS AND RESULTS Before coronary artery bypass grafting, 57 patients underwent late gadolinium enhancement (LGE) CMR and echocardiography at rest and dobutamine stress (DS). According to the degree of LGE, segments were allocated to groups of none, subendocardial (1-50%), subtotal (51-75%), and total transmural scars (>75%). Dysfunctional segments were identified by PLS or wall motion scores (WMS). The finding of normal/near normal resting WMS and PLS, excellently identified segments without transmural LGE (AUC 94.0 CI 90.6-97.3 and AUC 85.7 CI 79.0-92.3, respectively). However, the finding of akinesia did not necessarily indicate transmural scarring. The negative predictive value was high (99%, CI 98-100%) while the positive predictive value was low. Detection-rates for subendocardial LGE were low. CONCLUSION Normo- and slightly hypokinetic myocardium by resting WMS or strain detects the absence of transmural scars. However, the finding of severe hypo- and akinesia does not reliably predict transmural scarring, with no improvement by the addition of DS. Detection of predominant akinesia with less than two normo- or hypokinetic segments in the territory of a high-grade coronary stenosis or occlusion, warrants further examination by LGE-CMR.

Assessment of myocardial ischemia by strain dobutamine stress echocardiography and cardiac magnetic resonance perfusion imaging before and after coronary artery bypass grafting

Following coronary artery bypass grafting (CABG), testing for myocardial ischemia by noninvasive imaging is often hampered by false‐positive results. The aim of this study was to find test parameters with the best potential to identify myocardial ischemia in post‐CABG patients.

Antiplatelet Therapy During PCI for Patients with Stable Angina and Atrial Fibrillation

The pharmacological treatment options for anticoagulation in patients with atrial fibrillation (Afib) have increased with the introduction of novel oral anticoagulants, compared with earlier times, when vitamin K antagonist was the drug of choice. As they age, many Afib patients require percutaneous coronary intervention (PCI), necessitating antiplatelet medication in addition to anticoagulation therapy. Choosing the appropriate combination and duration of anticoagulation and antiplatelet therapies may be challenging in stable coronary artery disease (CAD) and even more complicated during and after coronary intervention with the introduction of additional antithrombotic drugs. In this article, we review the scientific basis for the recent guidelines for anticoagulation and antithrombotic therapy in patients with Afib and stable CAD before, during, and after elective PCI.