Superior Vena Cava Syndrome: An Umbrella Review

Superior vena cava syndrome (SVCS) is a medical emergency that encompasses an array of signs and symptoms due to obstruction of blood flow through the superior vena cava (SVC). It poses a significant healthcare burden due to its associated morbidity and mortality. Its impact on the healthcare system continues to grow due to the increasing incidence of the condition. This incidence trend has been attributed to the growing use of catheters, pacemakers, and defibrillators, although it is a rare complication of these devices. The most common cause of SVCS remains malignancies accounting for up to 60% of the cases. Understanding the pathophysiology of SVCS requires understanding the anatomy, the SVC drains blood from the right and left brachiocephalic veins, which drain the head and the upper extremities accounting for about one-third of the venous blood to the heart. The most common presenting symptoms of SVCS are swelling of the face and hand, chest pain, respiratory symptoms (dyspnea, stridor, cough, hoarseness, and dysphagia), and neurologic manifestations (headaches, confusion, or visual/auditory disturbances). Symptoms generally worsen in a supine position. Diagnosis typically requires imaging, and SVCS can be graded based on classification schemas depending on the severity of symptoms and the location, understanding, and degree of obstruction. Over the past decades, the management modalities of SVCS have evolved to meet the increasing burden of the condition. Here, we present an umbrella review providing an overall assessment of the available information on SVCS, including the various management options, their indications, and a comparison of the advantages and disadvantages of these modalities.

Clinical significance of the hemodynamic gain index in patients undergoing exercise stress testing and coronary computed tomography angiography

Background

Many hemodynamic parameters are used during exercise stress testing but provide limited information regarding obstructive coronary artery disease (CAD) when exercise is suboptimal. Hemodynamic gain index (HGI) is a recently developed and sensitive indicator of ischemia which has been associated with increased mortality.

Purpose

This study sought to evaluate the clinical impact of HGI in patients who underwent concomitant exercise testing and coronary computed tomography angiography (CCTA).

Methods

Consecutive patients from the executive health program between 2010 and 2018 were identified. Resting and peak heart rate (HR) and systolic blood pressure (SBP) were recorded. Framingham risk score (FRS), Duke treadmill score (DTS) and HGI [(HRpeak × SBPpeak) − (HRrest × SBPrest)] / (HRrest × SBPrest) were calculated. The latter was divided into quartiles. The presence or absence of any CAD on CCTA was confirmed. Multivariate analysis and artificial neural network were used to determine the independent predictors of obstructive CAD.

Results

There were 284 patients (mean age 53 years, 83% male). Mean HGI was 1.74±0.67, with severely blunted HGI cut-off of ≤1.25 (Quartile 4). Patients with blunted HGI were older, had higher FRS, and worse DTS. Patients with obstructive CAD showed lower HGI when compared to control (1.36±0.53 vs. 1.77±0.67, P-value 0.005) and had more prevalence of severely blunted HGI ≤1.25 (44% vs. 22%, P-value 0.019). In the multivariate analysis, after adjusting for traditional risk factors, HGI remained independent predictor of obstructive CAD while severely blunted HGI ≤1.25 was associated with 3-fold increased odds of obstructive CAD (P-value 0.05). Using artificial intelligence analysis, blunted HGI remained an independent predictor of obstructive CAD an area under the curve of 0.83 and 0.96, and normalized importance of HGI of 100% and 63%, respectively for different models.

Conclusions

Among patients who underwent concomitant exercise testing and CCTA, blunted HGI ≤1.25 was strongly associated with obstructive CAD after adjusting for traditional risk factors. HGI is robust, practical, and allows clinicians to reclassify patients, change management, and thus improve prognosis.

Funding Acknowledgement

Type of funding sources: None.

Clinical and angiographic success and safety comparison of coronary intravascular lithotripsy: An updated meta-analysis

Background

Intravascular lithotripsy (IVL) can be used to assist stent deployment in severe coronary artery calcifications (CAC).

Methods

Studies employing IVL for CAC lesions were included. The primary outcomes included clinical and angiographic success. The secondary outcomes, including lumen gain, maximum calcium thickness, and calcium angle at the final angiography site, minimal lumen area site, and minimal stent area site, were analyzed by the random-effects model to calculate the pooled standardized mean difference. Tertiary outcomes included safety event ratios.

Results

Seven studies (760 patients) were included. The primary outcomes: pooled clinical and angiographic success event ratio parentage of IVL was 94.4% and 94.8%, respectively. On a random effect model for standard inverse variance for secondary outcomes showed: minimal lumen diameter increase with IVL was 4.68 mm (p-value < 0.0001, 95% CI 1.69–5.32); diameter decrease in the stenotic area after IVL session was −5.23 mm (95 CI –22.6–12.8). At the minimal lumen area (MLA) and final minimal stent area (MSA) sites, mean lumen area gain was 1.42 mm² (95% CI 1.06–1.63; p < 0.00001) and 1.34 mm² (95% CI 0.71–1.43; p < 0.00001), respectively. IVL reduced calcium thickness at the MLA site (SMD −0.22; 95% CI −0.40–0.04; P = 0.02); calcium angle was not affected at the MLA site. The tertiary outcomes: most common complication was major adverse cardiovascular events (n = 48/669), and least common complication was abrupt closure of the vessel (n = 1/669).

Conclusions

Evidence suggests that IVL safely and effectively facilitates stent deployment with high angiographic and clinical success rates in treating severely calcified coronary lesions.

Swiss cheese interventricular septum presenting with catastrophic stroke: the potential role of ECG-gated CTA

Ventricular septal defect is a common congenital cardiac condition that presents in a variety of morphologies. Less commonly, when an individual patient is found to have multiple ventricular septal defects, the term “Swiss cheese ventricular septal defect” is applied. Although not routinely utilized in clinical practice, electrocardiogram (ECG)-gated computed tomographic angiography (CTA) has been shown to provide utility in detecting intracardiac shunts, demonstrating promise in preventing acute strokes secondary to a paradoxical embolus from occurring; this is especially important when atypical cardiac septa are suspected. This case seeks to illustrate how usage of ECG-gated CTA can assist in early detection and prevention of adverse outcomes resulting from an atypical presentation of a ventricular septal defect.

Outcomes of intravascular ultrasound versus optical coherence tomography guided percutaneous coronary angiography: A meta regression-based analysis

BACKGROUND

Studies comparing clinical outcomes with intravascular ultrasound (IVUS) versus optical coherence tomography (OCT) guidance for percutaneous coronary intervention (PCI) in patients presenting with coronary artery disease, including stable angina or acute coronary syndrome, are limited.

METHODS

We performed a detailed search of electronic databases (PubMed, Embase, and Cochrane) for randomized controlled trials and observational studies that compared cardiovascular outcomes of IVUS versus OCT. Data were aggregated for the primary outcome measure using the random-effects model as pooled risk ratio (RR). The primary outcome of interest was major adverse cardiac events (MACE), cardiac mortality, and all-cause mortality. Secondary outcomes included myocardial infarction (MI), stent thrombosis (ST), target lesion revascularization (TLR), and stroke.

RESULTS

A total of seven studies met the inclusion criteria, comprising 5917 patients (OCT n = 2075; IVUS n = 3842). OCT-PCI versus IVUS-guided PCI comparison yielded no statistically significant results for all the outcomes; MACE (RR 0.78; 95% confidence interval [CI], 0.57-1.09; p = 0.14), cardiac mortality (RR 0.97; 95% CI, 0.27-3.46; p = 0.96), all-cause mortality (RR 0.74; 95% CI, 0.39-1.39; p = 0.35), MI (RR 1.27; 95% CI, 0.52-3.07; p = 0.60), ST (RR 0.70; 95% CI, 0.13-3.61; p = 0.67), TLR (RR 1.09; 95% CI, 0.53-2.25; p = 0.81), and stroke (RR 2.32; 95% CI, 0.42-12.90; p = 0.34). Furthermore, there was no effect modification on meta-regression including demographics, comorbidities, lesion location, lesion length, and stent type.

CONCLUSIONS

In this meta-analysis, OCT-guided PCI was associated with no difference in clinical outcomes compared with IVUS-guided PCI.

P808 Association between left ventricular diastolic dysfunction and subclinical coronary artery calcification

Funding Acknowledgements

None

Background

Assessment of diastolic dysfunction (DD) by echocardiography is an integral part of the evaluation of patients with normal ejection fraction (EF) and symptoms suggestive of heart failure. However, many patients with DD are asymptomatic. Computed tomography calcium scoring (CTCS) is often used to assess patients at low-intermediate risk for coronary artery disease (CAD).

Aim

The purpose of this study is to evaluate the association of DD with subclinical coronary artery calcification.

Methods

Consecutive patients presenting for executive check-up who underwent resting transthoracic echocardiography followed by CTCS were retrospectively identified between January 2010 and December 2014. Two‑dimensional and tissue Doppler imaging parameters were analyzed for assessing and grading of DD. Coronary artery calcium (CAC) score was quantified.

Results

A total of 191 patients (mean age 52 ± 12 years, 17% age ≥ 65, 20% with diabetes) were included. Of them, 69 (36%) patients had DD. Patients with higher CAC score were older, had more comorbidities, lower e’ velocity, and were more likely to have DD. In the multivariate analysis, DD alone, age &gt; 65 years, or both were associated with almost 3-fold increase of subclinical atherosclerosis. After propensity analysis, DD was still associated with increased odds ratio (OR) for subclinical CAC (OR 3.66 [1.54-8.72], P = 0.03), and similarly for e’&lt; 10 cm/s. Compared to patients age &lt; 65 years and normal diastolic function, those age &gt; 65 years or DD had OR 3.49 (1.45-8.35) for subclinical coronary atherosclerosis (CAC &gt; 0), whereas those age &gt; 65 years and DD had OR 9.30 (2.00-42), (P = 0.005 and P = 0.004, respectively).

Conclusions

Our analysis suggests that DD was strongly associated with CAC &gt; 0 even after adjusting for age and comorbidities. Assessment of CAC as part of the routine clinical evaluation of patients with normal EF and atypical symptoms without a history of coronary atherosclerotic disease is warranted for further risk stratification.

Table 1

Abstract P808 Figure. Baseline characteristics

Cardiac involvement in hypereosinophilic syndrome

A 9-year-old boy with hypereosinophilic syndrome (HES) was referred for cardiac magnetic resonance (CMR) imaging following an abnormal echocardiogram that showed a large mass layered on the inferolateral wall of the left ventricle, causing secondary severe mitral regurgitation. Cardiac involvement in HES usually affects the ventricular apex. In our case, CMR confirmed the presence of a large mural thrombus of 0.9 cm × 4.2 cm. This unusual cardiac involvement in HES was diagnosed in its intermediate thrombotic stage. CMR is very sensitive and specific in staging the disease. It explained the etiology of mitral regurgitation and guided therapy, especially when echocardiography was nonconclusive.

Stress-induced Worsening of Left Ventricular Diastolic Function as a Marker of Myocardial Ischemia

Background:

Echocardiography has been the subject of interest in diagnosing diastolic dysfunction and estimating left ventricular filling pressures (LVFPs). The present study is set to estimate the correlation between the worsening of diastolic parameters and the evidence of inducible ischemia during an exercise stress echocardiography (SE) in comparison with the results of coronary computed tomographic angiogram (CCTA).

Methods:

A total of 191 consecutive patients from the executive screening program who underwent exercise SE followed by CCTA were evaluated. Baseline demographics, heart rate, and blood pressure measurements were extracted for analysis. Standard two-dimensional and tissue Doppler imaging parameters were analyzed. Diastolic function was graded at rest and peak exercise.

Results:

Patients who had worsening of diastolic function by at least one grade had had 2–3-fold higher odds of having abnormal SE. In addition, patients with worsening of diastolic function had higher stress LVFPs (E/e’ = 11.7 ± 2.7 vs. E/e’ 8.0 ± 2.0; P < 0.0001), more E/e’ change >25% (48% vs. 22%, P = 0.012), and were more likely to have obstructive coronary artery disease (CAD) on CCTA (23.8% vs. 9.2%; P = 0.045). A change in E/e’ >25% (stress-rest) was highly associated with a positive stress test and abnormal CCTA result. Patients with no change or improvement in diastolic function with stress had a 92% negative predictive value of having normal SE and 91% of normal/nonobstructive CCTA.

Conclusion:

A worsening of diastolic function and a change in E/e’ >25% (stress-rest) were associated with abnormal SE, positive stress test, and obstructive CAD when compared to CCTA results.

Comparison of three commercially available softwares for measuring left ventricular perfusion and function by gated SPECT myocardial perfusion imaging

BACKGROUND

The three softwares, Quantitative Perfusion SPECT (QPS), Emory Cardiac Toolbox, and 4 Dimension-Myocardial SPECT (4DM) are widely used with myocardial perfusion imaging (MPI) to determine perfusion defect size (PDS) and left ventricular (LV) function. There are limited data on the degree of agreement between these methods in quantifying the LV perfusion pattern and function.

METHODS AND RESULTS

In 120 consecutive patients who had abnormal regadenoson SPECT MPI with a visually derived summed stress score ≥4, the correlation between the softwares for measurements of PDS, reversible, and fixed defects was poor to fair (Spearman's ρ = 0.18-0.72). Overall, estimation of defect size was smaller by QPS and larger by 4DM. There was discordance among the softwares in 62% of the cases in defining PDS as small/moderate/large. The correlation between the softwares was better for measuring LVEF, volumes and mass (ρ = 0.84-0.97), and discrepant results for defining normal/mild-moderate/severe LV systolic dysfunction were prevalent in 28% of the patients.

CONCLUSION

There are significant differences between the softwares in measuring PDS as well as LV function, and more importantly in defining small, moderate, or large ischemic burden. These results suggest the necessity of using the same software when assessing interval changes by serial imaging.

The effect of bone marrow mononuclear stem cell therapy on left ventricular function and myocardial perfusion

BACKGROUND

Bone marrow stem cell (BMC) transfer is an emerging therapy with potential to salvage cardiomyocytes during acute myocardial infarction and promote regeneration and endogenous repair of damaged myocardium in patients with left ventricular (LV) dysfunction. We performed a meta-analysis to examine the association between administration of BMC and LV functional recovery as assessed by imaging.

METHODS AND RESULTS

Our meta-analysis included data from 32 trials comprising information on 1,300 patients in the treatment arm and 1,006 patients in the control arm. Overall, BMC therapy was associated with a significant increase in LV ejection fraction by 4.6% ± 0.7% (P < .001) (control-adjusted increase of 2.8% ± 0.9%, P = .001), and a significant decrease in perfusion defect size by 9.5% ± 1.4% (P < .001) (control-adjusted decrease of 3.8% ± 1.2%, P = .002). The effect of BMC therapy was similar whether the cells were administered via intra-coronary or intra-myocardial routes and was not influenced by baseline ejection fraction or perfusion defect size.

CONCLUSIONS

BMC transfer appears to have a positive impact on LV recovery in patients with acute coronary syndrome and those with stable coronary disease with or without heart failure. Most studies were small and a minority used a core laboratory for image analysis.

Relation of heart-rate recovery to new onset heart failure and atrial fibrillation in patients with diabetes mellitus and preserved ejection fraction

Diabetic autonomic neuropathy is a possible link between abnormal metabolism in type 2 diabetes mellitus (T2DM) and risk for atrial fibrillation (AF) and heart failure (HF). The aim of this study was to elucidate the association between attenuated heart rate recovery (HRR) and these manifestations of myocardial dysfunction in T2DM. Nine hundred fourteen consecutive patients with T2DM (mean age 56 ± 11 years, 508 men) without diabetes mellitus complications, with negative results on stress echocardiography, were enrolled. Patients with known cardiac disease were excluded. Demographics, clinical assessment, co-morbidities, and insulin use were collected prospectively. The association of HRR with new-onset HF and AF was sought using a Cox proportional-hazards model. There were 47 events (22 HF and 25 AF) during a median follow-up period of 7.8 years. Events were associated with age, exercise capacity, HRR, and left atrial volume index but not with baseline glycosylated hemoglobin, left ventricular mass index, or standard markers of diastolic function. In sequential Cox models for the combined outcomes, the model based on clinical data (age and gender; overall chi-square = 5.5) was not significantly improved by left atrial volume index (chi-square = 8.6, p = 0.10) or maximum METs (chi-square = 8.7, p = 0.07) but was significantly improved by adding HRR (chi-square = 19.7, p = 0.004). In addition, HRR provided significant incremental prognostic value regarding the composite end point (net reclassification improvement 19.2%, p = 0.04; integrated discrimination improvement 1.58%, p = 0.004). In conclusion, the association of HRR with subsequent HF and AF, independent of and incremental to left atrial volume index and other markers of abnormal cardiac structure and function, indicates a role for autonomic neuropathy as the link between metabolic and cardiac risk in patients with T2DM.

Implications of left bundle branch block in patient treatment

Left bundle branch block (LBBB) causes an abnormal pattern of cardiac activation and affects regional myocardial function. Although recognition of LBBB on the surface electrocardiogram is straightforward, dissecting its effect on patient treatment and outcome can be more challenging. The altered pattern of cardiac activation in LBBB causes electrical and mechanical ventricular dyssynchrony, influences ischemia detection on the surface electrocardiogram, and affects stress testing and imaging modalities dependent on wall motion and thickening. Restoration of synchrony by biventricular pacing can improve symptoms and longevity in carefully selected patients. The diagnostic, prognostic, and therapeutic implications of LBBB across this spectrum are discussed in this review.

Paradoxical septal motion from prior coronary artery bypass graft surgery does not impact left ventricular mechanical dyssynchrony by gated myocardial perfusion imaging

BACKGROUND

Phase analysis of gated myocardial perfusion imaging (MPI) provides automated and reproducible assessment of left ventricular (LV) mechanical dyssynchrony (LVMD) (phase standard deviation [SD]). Many patients undergoing gated MPI have history of prior coronary artery bypass graft surgery (CABG). The latter is often associated with paradoxical septal wall motion (PSM). The effect of prior CABG and PSM on LVMD has not been evaluated.

METHODS AND RESULTS

From the single-photon emission computed tomography (SPECT) and positron emission tomography (PET) MPI clinical database maintained at the Cleveland Clinic, we identified 200 consecutive patients with SPECT (100 control with normal LV ejection fraction [EF], MPI, and QRS < 120 ms; and 100 with LVEF < 35%), and 631 patients with LVEF < 35% with gated PET. Patients with QRS ≥ 120 ms, bundle branch block, ventricular pacing or isolated non-CABG surgery were excluded. There were 162 patients with gated SPECT (46 with prior CABG), and 568 with gated PET (220 with prior CABG) that were left for analysis. Phase SD was derived using Emory Cardiac Toolbox (ECTb) (for gated SPECT) and Corridor 4DM (4DM) (for gated SPECT and PET images). Multivariate linear regression analysis was performed to assess whether prior CABG was an independent predictor of worse LV mechanical dyssynchrony. After adjusting for patients' demographics, co-morbidities, medications, and MPI data, history of prior CABG was not and independent predictor of LV mechanical dyssynchrony (P = .67 with 4DM, P = .97 with ECTb) in patients undergoing gated SPECT or among patients undergoing gated PET imaging (P = .18).

CONCLUSIONS

Although paradoxical septal wall motion is commonly seen after cardiac surgery, prior CABG does not affect or impact LV mechanical dyssynchrony indices measured from gated SPECT or PET images. Whether dyssynchrony measurements with echocardiography that has higher temporal resolution might uncover intraventricular delays, remains to be determined.

Impact of body mass index on diastolic function in patients with normal left ventricular ejection fraction

Background:

Obesity is a major public health epidemic and is associated with increased risk of heart failure and mortality. We evaluated the impact of body mass index (BMI) on the prevalence of diastolic dysfunction (DD).

Methods:

We reviewed clinical records and echocardiogram of patients with baseline echocardiogram between 1996 and 2005 that showed normal left ventricular ejection fraction (LVEF). Diastolic function was labeled as normal, stage 1, stage 2 or stage 3/4 dysfunction. Patients were categorized as normal weight (BMI <25 kg m⁻²), overweight (25–29.9 kg m⁻²), obese (30–39.9 kg m⁻²) and morbidly obese (⩾40 kg m⁻²). Multivariable ordinal and ordinary logistic regression were performed to identify factors associated with DD, and evaluate the independent relationship of BMI with DD.

Results:

The cohort included 21 666 patients (mean (s.d.) age, 57.1 (15.1); 55.5% female). There were 7352 (33.9%) overweight, 5995 (27.6%) obese and 1616 (7.4%) morbidly obese patients. Abnormal diastolic function was present in 13 414 (61.9%) patients, with stage 1 being the most common. As BMI increased, the prevalence of normal diastolic function decreased (P<0.0001). Furthermore, there were 1733 patients with age <35 years; 460 (26.5%) and 407 (23.5%) were overweight and obese, respectively, and had higher prevalence of DD (P<0.001). Using multivariable logistic regression, BMI remained significant in both ordinal (all stages of diastolic function) and binary (normal versus abnormal). Also, obesity was associated with increased odds of DD in all patients and those aged <35 years.

Conclusions:

In patients with normal LVEF, higher BMI was independently associated with worsening DD.

The relation between left ventricular ejection fraction and perfusion defect size by gated SPECT myocardial perfusion imaging in patients with coronary artery disease

AIM

Left ventricular (LV) ejection fraction (EF) and perfusion defect size (PDS) provide independent and incremental prognostic information in patients with coronary artery disease (CAD). The purpose of this study was to examine the correlation between EF and PDS.

METHODS

LVEF and PDS were measured in 96 consecutive patients with CAD and abnormal perfusion scan using well-validated automated programs. The PDS was expressed as % of LV myocardium as total (reversible plus fixed), fixed or reversible.

RESULTS

The EF was 49±15% (range 17-84), the total PDS was 29±15% (2-77) and the fixed PDS was 20±13% (2-58). The end-diastolic volume (EDV) was 131±59 mL (29-342) and end-systolic volume (ESV) was 72±51 mL (4-283). There were moderate but significant correlations between EF and total PDS (r=-0.46, P<0.0001) and fixed PDS (r=-0.45, P<0.0001) but not with reversible PDS. In the subgroup analysis, the correlations were stronger in patients with history of prior coronary artery bypass grafting than without, and higher in men than women. The highest correlations were seen between EF and EDV in both men and women (r=-0.68 and -0.74 respectively, P<0.0001 each), and between EF and ESV (r =-0.80, P<0.0001).

CONCLUSION

Although there is a statistically significant correlation between PDS and EF, the correlation is not strong. This observation provides supportive evidence of why PDS and EF provide incremental prognostic information. It also supports the incremental prognostic merits of LV volume measurements.

Left ventricular dyssynchrony in patients with end-stage liver disease

BACKGROUND

Limited published data suggested that patients with end-stage liver disease (ESLD) might have "cirrhotic cardiomyopathy," which could have an earlier stage manifested by mechanical dyssynchrony before left ventricular (LV) dysfunction.

METHODS AND RESULTS

We studied consecutive patients with ESLD who had a stress-gated Tc-99m sestamibi myocardial perfusion imaging between 2008 and 2010 prior to liver transplant. Patients with LVEF < 50%, abnormal perfusion, or QRS ≥ 120 ms were excluded. Baseline demographics, co-morbidities, model for ESLD (MELD) score, LV volumes, mass, ejection fraction (EF), and dyssynchrony indices (standard deviation and bandwidth) were extracted. The phase indices were compared to a normal cohort. There were 179 patients with a mean age 53 ± 8 years, LVEF 72 ± 10%. Hepatitis C, non-alcoholic steatohepatitis, and alcohol abuse were the most common cause of liver cirrhosis (40%, 18%, and 14%, respectively). Patients with ESLD had similar standard deviation (14 ± 8° vs 15 ± 6°, P = NS) and bandwidth (41 ± 25° vs 42 ± 14°, P = NS) to the normal cohort. Only four patients (2%) had a standard deviation >27° (mean + 2 SD of the control group). The phase standard deviations and bandwidth similar in patients with MELD scores of ≤10, 11-18, 19-24, and ≥25 (P = NS for both). There was no correlation between the MELD score and standard deviation or bandwidth (r = -0.044 and -0.068, respectively, P = NS for both). Also, there was no correlation between the QTc and dyssynchrony indices. After 1-year follow-up, 22 patients died (12%). The dyssynchrony indices were similar among those who died and those who survived.

CONCLUSION

Patients with ESLD and normal EF have no evidence for LV dyssynchrony.

The effect of ranolazine on the vasodilator-induced myocardial perfusion abnormality

BACKGROUND

We previously reported that ranolazine improved myocardial ischemia during exercise myocardial perfusion imaging (MPI). Since the mechanism of reversible perfusion defects is different in exercise than vasodilator MPI, and based on the mechanism of action of ranolazine, we hypothesized that vasodilator stress MPI may fail to show improvement in myocardial perfusion pattern.

METHODS

Patients (n = 18) with known coronary artery disease and with reversible perfusion defects on a clinically indicated vasodilator stress MPI were re-studied 4 weeks after ranolazine (500-1000 mg PO BID) was added to their conventional treatment in an open-label trial. Perfusion pattern was assessed using automated methods.

RESULTS

The baseline left ventricular ejection fraction was 59% ± 14%. The total perfusion defect (measured by polar maps) was 22% ± 13% before and 21% ± 16% of LV myocardium after treatment (P = NS). The reversible defect size was 14% ± 10% before and 14% ± 11% of LV myocardium after treatment (P = NS). The automated-derived summed stress score was 12 ± 8 before and 12 ± 10 after treatment (P = NS) and the automated-derived summed difference score was 6 ± 5 before and 6 ± 5 after treatment (P = NS). Only 3 patients showed a decrease in reversible perfusion defect size with treatment.

CONCLUSION

Vasodilator stress MPI failed to show improvement in perfusion pattern after ranolazine treatment in most patients with baseline reversible defects. This is consistent with the unique anti-ischemic mechanism of ranolazine, which acts on the late I Na channel.

Safety of regadenoson in patients with end-stage liver disease

BACKGROUND

Regadenoson is a selective A(2A) receptor agonist that is used for vasodilator stress myocardial perfusion imaging (MPI). Since the drug is partially metabolized by the liver, its safety in patients with end-stage liver disease (ESLD) needs to be determined.

METHODS AND RESULTS

We studied 168 consecutive patients with ESLD who had regadenoson stress gated single photon emission computed tomography MPI between January 2008 and March 2010 before planned orthotopic liver transplantation and compared the hemodynamic responses and safety profile to 168 control patients. There were 72 women (43%) in ESLD versus 87 (52%) in the control group (P = .1). The patients with ESLD were younger (58 ± 7 vs 62 ± 12 years, P = .0002), but more likely to be Caucasians (P = .002). The MPI images were normal in 161 patients (96%) in each group. The left ventricular ejection fraction was 72 ± 10% in ESLD and 66 ± 11% in the control patients (P = .0001). The heart rate increase in response to regadenoson was lower in patients with ESLD than in the control group (16 ± 11 vs 23 ± 16 bpm, P = .0001), but the changes in systolic and diastolic blood pressures were similar (-9 ± 12 vs -11 ± 14 mmHg and -6 ± 8 vs -7 ± 10 mmHg, respectively, P = NS). There were no deaths or medication-related adverse events that required hospitalization in either group within 30 days of the study.

CONCLUSION

This is the first study to document the tolerability and safety profile of regadenoson in patients with ESLD.

Impact of ischemia on left ventricular dyssynchrony by phase analysis of gated single photon emission computed tomography myocardial perfusion imaging

BACKGROUND

There is increasing awareness of the value of phase analysis of gated tomographic myocardial perfusion imaging in assessing left ventricular (LV) dyssynchrony. A concern repeatedly raised in many studies is whether reversible defects in the stress images "ischemia" could affect the phase-derived standard deviation and bandwidth, the two commonly used dyssynchrony indices. We hypothesized that the stress and rest images should provide comparable information because the images are acquired 1 hour after the tracer injection.

METHODS AND RESULTS

We studied two groups of patients with normal LV ejection fraction and no fixed perfusion defects. In group-1 (N = 20), the patients had reversible perfusion defects involving > 10% of the LV myocardium and in group-2 (N = 20), the patients had normal images. All patients underwent stress/rest-gated single photon emission computed tomography sestamibi imaging (the stress study was acquired with the lower dose) between January and March 2010. Patients with left bundle branch block or ventricular pacing were excluded. The patients in group-1 had a mean age of 61 ± 9 years, 65% were men, 75% Caucasians, and 70% had known prior coronary artery disease. The size of the reversible perfusion defect was 20 ± 13% (range 11%-50%) of the LV myocardium. The rest and stress phase-derived standard deviation (16 ± 6° vs 18 ± 8° and 16 ± 7° vs. 19 ± 6°) and the rest and stress bandwidth (42 ± 14° vs 46 ± 16° and 45 ± 17° vs 52 ± 12°), respectively, (P = NS for all) were similar in the two groups. The change (stress-rest) in standard deviation and bandwidth in groups 1 and 2 were not statistically significant (0.2 ± 3.1° vs 1.4 ± 4.7°, and 2 ± 13° vs 5 ± 13°, respectively, P = NS). There was no significant change from rest to stress in the standard deviation and the bandwidth in group-1 (P = .8 and .4, respectively) and group-2 (P = .2 and .08, respectively). There was no correlation between the size of the reversible perfusion defect and the change in phase standard deviation or bandwidth (r = 0.07 and 0.12, respectively, P = NS).

CONCLUSIONS

The presence of even a large reversible perfusion defect does not alter the indices of mechanical dyssynchrony by phase analysis. Further, comparable information is obtained whether using a low dose or a high dose of the radiotracer.

Left ventricular mechanical dyssynchrony by phase analysis of gated single photon emission computed tomography in end-stage renal disease

The presence and degree of left ventricular (LV) dyssynchrony in patients with end-stage renal disease (ESRD) has not been well studied. We hypothesized that these patients would be more likely to have mechanical dyssynchrony than a control cohort. The indexes of LV mechanical dyssynchrony were measured by automated analysis of gated single photon emission computed tomography myocardial perfusion imaging in 290 patients with ESRD and 109 control patients. Only patients with normal myocardial perfusion imaging findings and a narrow QRS duration were included. The following variables were derived: LV ejection fraction (EF), volume, mass, and 2 indexes of dyssynchrony, the standard deviation and bandwidth. The standard deviation and bandwidth were significantly greater in those with ESRD (23° ± 13° vs 15° ± 6° and 65° ± 40° vs 42° ± 14°, respectively, p <0.001 for each). The LV volumes and LV mass were significantly lower and LVEF significantly greater in the control group than in the patients with ESRD (p <0.001 for each). The subgroup of 217 patients with ESRD and normal LVEF also had a significantly greater standard deviation and bandwidth than did the control group (21° ± 12° and 57° ± 35°, p <0.001 for each). However, their values were lower than those of the 73 patients with ESRD and a LVEF <50% (30° ± 13° and 90° ± 45°, p <0.001 for each). Finally, 25 patients (9%) with ESRD and none of the control group had a standard deviation >43° (p = 0.01). In conclusion, patients with ESRD had significantly more mechanical dyssynchrony than did the control group, even in absence of electrical dyssynchrony and abnormal LV perfusion or function.

The impact of viability assessment using myocardial perfusion imaging on patient management and outcome

BACKGROUND

Prior studies show that ischemic cardiomyopathy (ICM) patients with substantial viable myocardium have better survival with coronary revascularization (CR) than medical therapy (MT). When myocardial perfusion imaging (MPI) is used, the analysis is often based on visual scoring. We sought to determine the value of automated quantitative viability analysis in guiding management and predicting outcome.

METHODS

We identified 246 consecutive ICM patients who had rest-redistribution gated SPECT thallium-201 MPI. Size and severity of perfusion defects were assessed by automated method. Regions with <50% activity vs normal were considered nonviable. Mortality was verified against the social security death index database.

RESULTS

Of the 246 patients, 37% underwent CR within 3 months of MPI. The initial images showed a total perfusion defect size of 32 +/- 17%, redistribution of 3.5 +/- 4.6% and nonviable myocardium of 13 +/- 14%LV. Using multivariate logistic regression analysis, independent predictors of CR included chest pains (OR 2.74) and rest-delayed transient ischemic dilatation (OR 4.49), while a prior history of CR or ventricular arrhythmias favored MT. The cohort was followed-up for 41 +/- 30 m during which 111 patients (45%) died. Survival was better with CR than MT (P < .0001). For CR, survival was better for those with a smaller area of nonviable myocardium (risk of death increased by 5%/1% increase in size of nonviable myocardium, P = .009) but this was not seen in MT. CR had a mortality advantage over MT when the area of nonviable myocardium was

CONCLUSIONS

Automated quantitative analysis of MPI is useful in predicting survival in ICM, but the decision for or against CR is a complex one as it depends on multiple other factors and "viability testing" is just one variable that needs to be incorporated in the decision-making process.

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MESH Headings

• Cardiac-Gated Single-Photon Emission Computer-Assisted Tomography
• Cardiomyopathies/diagnostic imaging
• Cardiomyopathies/etiology
• Cardiomyopathies/physiopathology
• Cardiomyopathies/surgery
• Coronary Artery Bypass
• Female
• Humans
• Kaplan-Meier Estimate
• Male
• Middle Aged
• Myocardial Ischemia/complications
• Myocardial Perfusion Imaging
• Proportional Hazards Models
• Radioisotopes
• Stroke Volume
• Thallium Radioisotopes

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Affiliation(s)

Fadi G Hage Division of Cardiovascular Disease, University of Alabama at Birmingham, Zeigler Research Building 1024, 1530 3rd AVE S, Birmingham, AL 35294, USA.
Rajesh Venkataraman
Wael Aljaroudi
Paco E Bravo
Joel McLarry
Michael Faulkner
Jaekyeong Heo
Ami E Iskandrian

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Correlation between serum cardiac markers and myocardial infarct size quantified by myocardial perfusion imaging in patients with hypertrophic cardiomyopathy after alcohol septal ablation

Myocardial infarct (MI) size is a well-established prognostic marker but the association of serum markers with MI size, as measured by myocardial perfusion imaging (MPI), has not been well studied in patients with hypertrophic cardiomyopathy (HC) after alcohol septal ablation (ASA). Creatine kinase (CK), CK-MB, troponin I, and brain natriuretic peptide were measured before and at multiple points after ASA in patients with HC and were correlated with MI size measured by MPI. MPI at rest was performed in 54 patients with HC at a median of 2 days after ASA. CK, CK-MB, and troponin I increased after ASA to peak levels at 12 hours and their cumulative levels (area under the curve) showed significant correlation with size of MI by MPI (r = 0.544, 0.408, and 0.477, p <0.001, 0.003, and 0.001, respectively). The best marker was level of CK at 12 hours (r = 0.609, p <0.0001) after ASA. Brain natriuretic peptide level did not change significantly after ASA (p = 1.0) and only weakly correlated with MI size by MPI (r = 0.130, p = 0.007). In conclusion, CK, CK-MB, and troponin I measured at 12 hours, at peak, and as the area under the curve correlated well with infarct size, but CK level at 12 hours was the best marker. CK continues to be a useful marker of MI size despite the introduction of newer, more specific markers, especially when infarct onset is known with certainty as in patients with HC undergoing ASA.

Safety of regadenoson in patients with end-stage renal disease

Regadenoson is a selective A(2A) receptor agonist that was recently approved by the Food and Drug Administration for vasodilator stress myocardial perfusion imaging. Because the drug is cleared by renal excretion, its safety in patients with end-stage renal disease (ESRD) needs to be determined. We studied 277 consecutive patients with ESRD who had undergone regadenoson stress gated single photon emission computed tomography myocardial perfusion imaging and compared their side effect profile and safety outcome to those of 134 patients with normal kidney function. The ESRD group included 164 men (59%) and the control group included 73 men (54%; p = NS). The patients with ESRD were younger than the controls (52 +/- 11 years vs 61 +/- 12 years; p <0.001). The myocardial perfusion imaging findings were abnormal in 53 patients (19%) with ESRD and in 24 patients in the control group (18%; p = NS). The left ventricular ejection fraction was 57 +/- 12% in the ESRD group and 64 +/- 12% in the control group (p <0.001). The changes in heart rate and systolic blood pressure (from baseline to peak stress) were 20 +/- 12 beats/min versus 22 +/- 13 beats/min and -11 +/- 24 mm Hg versus -12 +/- 23 mm Hg in the ESRD and control groups, respectively (p = NS for both). Very few patients in either group reported symptoms during the stress test. No medication-related hospitalizations, serious events, or death occurred in either group within 30 days of the study. In conclusion, this is the first study to document the safety of regadenoson in a large number of patients with ESRD. The drug was well tolerated, and the hemodynamic and side effect profiles were similar to those of patients with normal renal function.