Decrease in cardiac catheterization and MI during COVID pandemic

The consequences of severe acute viral respiratory syndrome (COVID 19) pandemic include collateral effects, one of which has been the significant reduction in routine hospital work. With widespread reports indicating reduction of cardiac procedures including MI presentation to hospitals, we aimed to analyze the local data over a 10-week period during lockdown in a tertiary cardiac centre Catheter Laboratory in England.

Methods

We conducted a retrospective review of the coronary catheterisation procedures and admissions with MI over the peak COVID-19 pandemic 10-week period (23rd March-30th May) in 2020, compared with the same 10-week period (25th March-2nd June) in 2019.

Results

In 2019, 539 patients were admitted to the Cath lab for coronary catheterisation (M = 385:F = 154; mean age 65 years; STEMI = 186, NSTEMI = 192, elective = 161). In 2020, during peak period of COVID19 pandemic in England, a total of 278 patients were admitted for coronary catheterisation over the 10-week period (M = 201:F = 77; mean age 60.5 years; STEMI = 132, NSTEMI = 118, elective = 28). During peak COVID19 pandemic, this represents a 48.4% drop in all coronary catheterisations. The reduction in STEMI was 29% (54 less), in NSTEMI was 38.9% (74 less) and elective procedures dropped by 83% (133 less).

Conclusion

During peak COVID hospital admission period in England, we report a 48.5% reduction in coronary catheterisation in our tertiary hospital. These results are consistent with reports from other countries, and highlight the worrying potential consequences for these patients arising from delays in presentation with MI, and the challenges for restoring services post-pandemic.

Early presentation of dilated cardiomyopathy as a part of seroconversion illness in human immunodeficiency virus infection

It has been debated whether dilated cardiomyopathy seen in patients with acquired immune deficiency syndrome is caused by the virus itself or by the combination of other factors such as presence of opportunistic pathogens and/or severe immunosuppression. This paper describes the first reported case of a patient with human immunodeficiency virus (HIV) infection presenting with dilated cardiomyopathy during his acute seroconversion illness. Presence of cardiac involvement at a very early stage of HIV infection with no evidence of opportunistic infections, or immunosuppression with high CD4 count indicates that HIV may itself be a cardiac pathogen. This case also illustrates the importance of testing for HIV infection as part of the assessment of any patient presenting with myocarditis or dilated cardiomyopathy.

Successful use of the Heartrail III catheter as a stent delivery catheter following failure of conventional techniques

The Terumo "five in six" system involves insertion of an extra length, 5 Fr Terumo guide catheter (Heartrail, Terumo) into a standard 6 Fr guide catheter so that the tip protrudes beyond the 6 Fr guide. This system increases backup support and has been used successfully to advance balloon catheters across chronic total occlusions. We describe the use of this system to facilitate extra deep intubation, enabling distal stent delivery beyond proximal points of obstruction that had been unsuccessful using more conventional techniques.

Recurrent stent thrombosis associated with lupus anticoagulant due to renal cell carcinoma

A case is presented of recurrent stent thrombosis unexplained by angiographic appearance, which subsequently revealed a diagnosis of antiphospholipid syndrome secondary to renal cell carcinoma.

Effects of coronary revascularisation on myocardial blood flow and coronary vasodilator reserve in hibernating myocardium

OBJECTIVE

Previous studies have suggested that resting myocardial blood flow is within normal limits in most chronically dysfunctional left ventricular segments which improve function after coronary artery revascularisation (hibernating myocardium). The aim of this study was to assess myocardial blood flow and coronary vasodilator reserve in hibernating myocardium before and after coronary revascularisation.

PATIENTS AND METHODS

30 patients with multivessel coronary disease undergoing coronary revascularisation (21 patients with bypass grafting and nine with coronary angioplasty), and 21 age and sex matched healthy volunteers (controls). Myocardial blood flow (MBF, ml/min/g) was measured by positron emission tomography using oxygen-15 water at rest and after dipyridamole (MBFdip, 0.56 mg/kg in four minutes). Coronary vasodilator reserve was calculated as MBFdip/MBF. Regional wall motion was assessed with echocardiography.

RESULTS

Before revascularisation there were 48 remote and 275 dysfunctional myocardial segments, of which 163 (59%) improved function after revascularisation (hibernating). In hibernating segments coronary vasodilator reserve before revascularisation was significantly lower than in remote segments (1.97 (0.7), p < 0.0001) and controls (3.2 (1.5), p < 0.0001). In hibernating segments, myocardial blood flow remained unchanged after revascularisation (0.94 (0.3) v 0.95 (0.3) ml/min/g, p = 0.3) while coronary vasodilator reserve increased (1. 47 (0.7) v 1.98 (1.0), p < 0.0001). Myocardial blood flow was similar in remote, hibernating segments before and after revascularisation and in controls.

CONCLUSIONS

This study confirms that myocardial blood flow at rest in hibernating myocardium is within normal limits in most segments, and that hibernating myocardium is characterised by an impaired coronary vasodilator reserve which improves significantly after coronary revascularisation.

Efficacy of coronary angioplasty for the treatment of hibernating myocardium

OBJECTIVES

To determine the efficacy of coronary angioplasty as the sole method of revascularisation in patients with coronary artery disease and chronically dysfunctional but viable myocardium (hibernating myocardium), and to assess the effect of restenosis on functional outcome.

DESIGN AND PATIENTS

24 consecutive patients with hibernating myocardium were studied. Positron emission tomography was used to assess myocardial viability, blood flow, and flow reserve. One patient refused angioplasty, one had bypass surgery, and one died while waiting for an elective procedure. The procedure failed in three patients. The remaining 18 patients had repeat echocardiography, 15 had repeat coronary angiography, and nine had repeat assessments of blood flow and flow reserve at mean (SD) 17 (2) weeks after angioplasty. In three patients restenosis was documented.

RESULTS

The wall motion score index in the revascularised territories improved from 1.71 (0.37) to 1.34 (0.47) (p = 0.008). Thirty of 51 dysfunctional segments improved in territories without restenosis compared with three of 14 in restenosed territories (p = 0.001). Hibernating and normal segments had comparable flows (0.82 (0.26) v 0.89 (0.24) ml/min/g; NS) while flow reserve was lower in hibernating segments (1.55 (0.68) v 2.07 (1.08); p = 0.03). In segments without restenosis flow reserve improved from 2.03 (1.25) to 2.33 (1.4) (p = 0.03). Sensitivity, specificity, and positive and negative predictive accuracy of the viability study were 97%, 77%, 82%, and 96%, respectively. After excluding patients with restenosis, specificity and positive predictive accuracy improved to 90% and 93%.

CONCLUSIONS

Angioplasty improves function in hibernating myocardium, and restenosis prevents recovery; hibernating myocardium is characterised by an impairment of flow reserve; restenosis affects the diagnostic accuracy of viability studies.

Coronary revascularization in the treatment of moderate and severe postischemic left ventricular dysfunction

Chronic postischemic left ventricular (LV) dysfunction can improve following coronary revascularization (hibernating myocardium). However, it is not clear whether the severity of LV dysfunction determines functional outcome after revascularization and the accuracy of tests to predict myocardial viability. We studied 47 patients with coronary artery disease and chronic LV dysfunction. Before coronary bypass, patients underwent (18F)2-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) during euglycemic hyperinsulinemic clamp to assess viability. Global and regional LV function were assessed before and 4 to 6 months after surgery. Patients were arbitrarily divided into 2 groups with moderate and severe LV dysfunction. Group 1 (n = 26) had an ejection fraction (EF) of < or = 30% and group 2 (n = 21) > 30%. After bypass, the EF (22+/-6% vs 31+/-10%; p <0.0001) and global wall motion score (WMS) (2.05+/-0.39 vs 1.56+/-0.34; p <0.001) improved in group 1, whereas the EF (43+/-9% vs 43+/-12%; p = NS) was unchanged in group 2, although WMS tended to improve (1.42+/-0.38 vs 1.32+/-0.39; p = 0.09). The proportion of dysfunctional segments (72% vs 32%; p <0.0001) and FDG uptake in these segments (0.44+/-0.15 vs 0.34+/-0.15 micromol/g/min, p <0.0001) were greater in group 1 than in group 2. The baseline EF influenced the predictive accuracy of PET, with highest positive predictive accuracy in group 2 and highest negative predictive accuracy in group 1. Thus, coronary revascularization has the potential for greatest benefit in patients with the most severe dysfunction, but with evidence of viability, and the entity of LV dysfunction affects the predictive accuracy of viability studies.

Measurement of myocardial blood flow with oxygen-15 labelled water: comparison of different administration protocols

Positron emission tomography (PET) in conjunction with C15O2 or H215O can be used to measure myocardial blood flow (MBF) and tissue fraction (TF), i.e. the fraction of the tissue mass in the volume of the region of interest. However, with C15O2 inhalation, the tissue fraction in the septum is overestimated. Bolus injection of H215O together with arterial cannulation gives very precise results but is invasive. The purpose of this study was to develop a method which circumvents these problems. A four-parameter model with parameters for MBF, TF and spill-over fractions from both left and right ventricular cavities was developed. This method was compared with a three-parameter model (no right ventricular cavity spill-over) in both septal and non-septal regions of interest for three different administration protocols: bolus injection of H215O, infusion of H215O and inhalation of C15O2. It was found that MBF can be measured with intravenous administration of H215O without the requirement for arterial cannulation. The four-parameter protocol with bolus injection was stable in clinical studies. The four-parameter model proved essential for the septum, where it gave highly significantly better fits than did the three-parameter model (P<0.00003 in each of 15 subjects). Administration of H215O together with this four-parameter model also circumvented the problem of overestimation of TF in the septum seen with C15O2 inhalation. In addition, the radiation dose of H215O protocols is lower than that of C15O2 inhalation. Using a left atrial input curve instead of a left ventricular cavity input curve gave the same mean MBF and TF.

Glucose-insulin-potassium therapy for treatment of acute myocardial infarction: an overview of randomized placebo-controlled trials

BACKGROUND

Glucose-insulin-potassium (GIK) therapy has been advocated for the treatment of acute myocardial infarction. However, the results from the clinical trials have been inconclusive, largely because of the small number of patients recruited and discrepancies between protocols used in these studies.

METHOD AND RESULTS

A systematic MEDLINE search for all the randomized placebo-controlled studies of GIK therapy in acute myocardial infarction was made, and a meta-analysis of the mortality data was performed. Fifteen trials were identified, 5 were excluded because of poor randomization, and 1 was excluded because recruitment was limited to diabetic patients. The 9 remaining trials with a total of 1932 patients were included in the analysis. Hospital mortality was reduced from 21% (205 of 972 patients) in the placebo group to 16.1% (154 of 956) in the GIK group (P=.004; odds ratio, 0.72; 95% confidence interval [CI], 0.57 to 0.90). The proportional mortality reduction was 28% (CI, 10% to 43%). The number of lives saved per 1000 patients treated was 49 (95% CI, 14 to 83).

CONCLUSIONS

The findings indicate that GIK therapy may have an important role in reducing the in-hospital mortality after acute myocardial infarction. The value of this therapy in the era of thrombolysis and acute revascularization by primary angioplasty can be fully resolved only by conducting a large randomized mortality study.

Significance of the Thrombolysis in Myocardial Infarction scoring system in assessing infarct-related artery reperfusion and mortality rates after acute myocardial infarction

Thrombolysis in Myocardial Infarction (TIMI) flow scores were originally devised as semiquantitative angiographic measures of coronary artery perfusion. Several studies have indicated an important relation between different TIMI flow grades at 90 minutes after thrombolysis and clinical outcome. To further evaluate this relation we conducted a metaanalysis of all angiographic, postinfarction trials that studied the relation between individual 90-minute TIMI flow grades and mortality rates. In 4687 pooled patients, the mortality rate was lowest in patients with TIMI grade 3 flow (3.7%) and significantly lower than those with TIMI 2 (6.6%, p = 0.0003; odds ratio 0.55; 95% confidence interval [CI] 0.4% to 0.76%) or TIMI 0/1 flow (9.2%, p < 0.0001; odds ratio 0.38; 95% CI 0.29% to 0.5%). The mortality rate difference between TIMI grade 2 and TIMI grade 0/1 patients was also significant (p = 0.02; odds ratio 0.7; 95% CI 0.51% to 0.94%). This study confirms the importance of achieving rapid and complete reperfusion after acute myocardial infarction with the best outcome associated with 90-minute TIMI 3 flow. Furthermore, it shows that although TIMI 2 flow (partial perfusion) is not equivalent to TIMI 3 flow, it nevertheless still confers a significant survival benefit compared with TIMI flow 0/1.

Histological surprise: callosal tuberculoma presenting as malignant glioma

A tumour which on CT is clearly intrinsic, irregular, exhibits patchy enhancement with contrast, and invades periventricular tissues, especially the corpus callosum, is very likely to be a glioma and may not be biopsied. A case is presented with these radiological features in which the tumour proved to be a tuberculoma, with complete clinical and radiological resolution after antituberculous chemotherapy.

Acute myocardial infarction: strategies for thrombolytic therapy

Thrombolytic therapy has revolutionised the treatment of acute myocardial infarction. This has led to a need for rapid and accurate diagnosis of this condition, provision of a triage protocol to achieve initiation of thrombolytic therapy as soon as the diagnosis has been made, and knowledge of the benefit:risk ratio of thrombolytic therapy in different subgroups of patients to allow the most effective use of these agents without compromising patient safety.

Clinical assessment following coronary revascularization

There remains a need to establish adequate protocols for investigating the short- and long-term follow-up of revascularization procedures. For coronary angioplasty the most reliable basis for decision-making in managing patients is the symptomatology of the patient. For bypass surgery a protocol should be established to evaluate patients late, at 5 to 10 years following bypass surgery, in particular those with saphenous vein grafting, as graft and patient survival begins to fall after this period. Investigation after this may be too late for many patients who may already have several occluded grafts and poor left ventricular function, two of the most important prognostic factors post bypass surgery. The improvement and refinement of non-invasive investigations has led to a better understanding of the value and limitations of many of these tests, but it is particularly important that the limitations of many investigation are fully appreciated when they are used to influence clinical decisions. In this regard, a study comparing and integrating the predictive value of the persistence or return to symptoms, a positive non-invasive test, and a positive invasive test would surely prove invaluable.