Prognostic value of combined coronary CT angiography and myocardial perfusion imaging in women and men

AIMS

Combined anatomical and functional imaging enables detection of non-obstructive and obstructive coronary artery disease (CAD) as well as myocardial ischaemia. We evaluated sex differences in disease profile and outcomes after combined computed tomography angiography (CTA) and positron emission tomography (PET) perfusion imaging in patients with suspected obstructive CAD.

METHODS AND RESULTS

We retrospectively evaluated 1948 patients (59% women) referred for coronary CTA due to suspected CAD during the years 2008-2016. Patients with a suspected obstructive lesion on coronary CTA (n = 657) underwent 15O-water PET to assess stress myocardial blood flow (MBF). During a mean follow-up of 6.8 years, 182 adverse events (all-cause death, myocardial infarction, or unstable angina) occurred. Women had more often normal coronary arteries (42% vs. 22%, P < 0.001) and less often abnormal stress MBF (9% vs. 28%, P < 0.001) than men. The annual adverse event rate was lower in women vs. men (1.2% vs. 1.7%, P = 0.02). Both in women and men, coronary calcification, non-obstructive CAD, and abnormal stress MBF were independent predictors of events. Abnormal stress MBF was associated with 5.0- and 5.6-fold adverse event rates in women and men, respectively. There was no interaction between sex and coronary calcification, non-obstructive CAD, or abnormal stress MBF in terms of predicting adverse events.

CONCLUSION

Among patients evaluated for chronic chest pain, women have a lower prevalence of ischaemic CAD and a lower rate of adverse events. Combined coronary CTA and PET myocardial perfusion imaging predict outcomes equally in women and men.

The impact of diabetes on the relationship of coronary artery disease and outcome: a study using multimodality imaging

BACKGROUND

Patients with prediabetes or diabetes are at increased risk of developing cardiovascular disease and adverse outcomes. First-line coronary computed tomography angiography (CTA) followed by selective use of positron emission tomography (PET) myocardial perfusion imaging is a feasible strategy to diagnose and risk-stratify patients with suspected coronary artery disease (CAD). The aim of the present study was to study whether diabetes changes the relationship of CAD and long-term outcome.

METHODS

We retrospectively identified consecutive symptomatic patients who underwent coronary CTA for suspected CAD. In patients with suspected obstructive CAD on CTA, myocardial ischemia was evaluated by ¹⁵O-water PET myocardial perfusion imaging. The relationship of the phenotype of CAD and long-term outcome in patients with no diabetes, prediabetes, or type 2 diabetes was investigated. A composite endpoint included all-cause mortality, myocardial infarction (MI), and unstable angina pectoris (UAP).

RESULTS

A total of 1743 patients were included: 1214 (70%) non-diabetic, 259 (15%) prediabetic, and 270 (16%) type 2 diabetic patients. During 6.43 years of median follow-up, 164 adverse events occurred (106 deaths, 41 MIs, 17 UAPs). The prevalence of normal coronary arteries on CTA was highest in the non-diabetic patients (39%). The prevalence of hemodynamically significant CAD (abnormal perfusion) increased from 14% in non-diabetic patients to 20% in prediabetic and 27% in diabetic patients. The event rate was lowest in patients with normal coronary arteries and highest in patients with concomitant type 2 diabetes and hemodynamically significant CAD (annual event rate 0.2% vs. 4.7%). However, neither prediabetes nor diabetes were independent predictors of the composite adverse outcome after adjustment for the clinical risk factors and imaging findings.

CONCLUSIONS

Coronary CTA followed by selective downstream use of PET myocardial perfusion imaging predicts long-term outcome similarly in non-diabetic and diabetic patients.

Extensive and balanced reduction of myocardial blood flow in patients with suspected obstructive coronary artery disease: 15O-water PET study

BACKGROUND

Detection of obstructive coronary artery disease (CAD) by stress myocardial perfusion imaging (MPI) is conventionally based on relative differences in perfusion. This may lead to either underestimation of the extent of myocardial ischemia, or the ischemia might be completely missed in case of balanced perfusion reduction. Using absolute quantification of myocardial blood flow (MBF) by positron emission tomography (PET), we evaluated how common are extensive and balanced myocardial perfusion abnormalities in symptomatic patients with suspected obstructive CAD.

METHODS AND RESULTS

Among 758 consecutive symptomatic patients undergone coronary computed tomography angiography (CTA), 286 patients subsequently underwent quantitative 15O-water adenosine-stress PET MPI to assess the hemodynamic significance of suspected obstructive stenosis. Out of these, 46 (16%) patients had reduced (≤2.3 ml/g/min) absolute stress MBF in all three standard coronary territories (LAD, LCX, RCA). Subsequently, relative stress MBF in each coronary territory was calculated, considering a territory with the highest absolute stress MBF as a reference region. Among the 46 patients, 72% had significant regional heterogeneity in myocardial perfusion (defined as having ≥1 territory with relative stress MBF <80%) while the remaining 28% (4.5% of the whole MPI cohort) showed balanced perfusion reduction (all relative MBF values ≥80%).

CONCLUSIONS

Among symptomatic patients with suspected obstructive stenosis on coronary CTA, quantitative PET revealed that 16% of patients had reduced stress MBF involving all three coronary artery territories, of whom approximately one third showed balanced reduction. Thus, in 4.5% of the patients the perfusion abnormalities could have been missed by conventional relative MPI analysis.

Global and segmental absolute stress myocardial blood flow in prediction of cardiac events: [15O] water positron emission tomography study

Purpose

We evaluated the value of reduced global and segmental absolute stress myocardial blood flow (sMBF) quantified by [¹⁵O] water positron emission tomography (PET) for predicting cardiac events in patients with suspected obstructive coronary artery disease (CAD).

Methods

Global and segmental sMBF during adenosine stress were retrospectively quantified in 530 symptomatic patients who underwent [¹⁵O] water PET for evaluation of coronary stenosis detected by coronary computed tomography angiography.

Results

Cardiovascular death, myocardial infarction, or unstable angina occurred in 28 (5.3%) patients at a 4-year follow-up. Reduced global sMBF was associated with events (area under the receiver operating characteristic curve 0.622, 95% confidence interval (95% CI) 0.538–0.707, p = 0.006). Reduced global sMBF (< 2.2 ml/g/min) was found in 22.8%, preserved global sMBF despite segmentally reduced sMBF in 35.3%, and normal sMBF in 41.9% of patients. Compared with normal sMBF, reduced global sMBF was associated with the highest risk of events (adjusted hazard ratio (HR) 6.970, 95% CI 2.271–21.396, p = 0.001), whereas segmentally reduced sMBF combined with preserved global MBF predicted an intermediate risk (adjusted HR 3.251, 95% CI 1.030–10.257, p = 0.044). The addition of global or segmental reduction of sMBF to clinical risk factors improved risk prediction (net reclassification index 0.498, 95% CI 0.118–0.879, p = 0.010, and 0.583, 95% CI 0.203–0.963, p = 0.002, respectively).

Conclusion

In symptomatic patients evaluated for suspected obstructive CAD, reduced global sMBF by [¹⁵O] water PET identifies those at the highest risk of adverse cardiac events, whereas segmental reduction of sMBF with preserved global sMBF is associated with an intermediate event risk.

Coronary computed tomography angiography derived risk score in predicting cardiac events

BACKGROUND

We evaluated the prognostic value of an integrated atherosclerosis risk score combining the markers of coronary plaque burden, location and composition as assessed by computed tomography angiography (CTA).

METHODS

922 consecutive patients underwent CTA for suspected coronary artery disease (CAD). Patients without atherosclerosis (n = 261) and in whom quantitative CTA analysis was not feasible due to image quality, step-artefacts or technical factors related to image acquisition or data storage (n = 153) were excluded. Thus, final study group consisted of 508 patients aged 63 ± 9 years. Coronary plaque location, severity and composition for each coronary segment were identified using automated CTA quantification software and integrated in a single CTA score (0-42). Adverse events (AE) including death, myocardial infarction (MI) and unstable angina (UA) were obtained from the national healthcare statistics.

RESULTS

There were a total of 20 (4%) AE during a median follow-up of 3.6 years (9 deaths, 5 MI and 6 UA). The CTA risk score was divided into tertiles: 0-6.7, 6.8-14.8 and > 14.8, respectively. All MI (n = 5) and most of the other AE occurred in the highest risk score tertile (3 vs. 3 vs. 14, p = 0.002). After correction for age and gender, the CTA risk score remained independently associated with AE.

CONCLUSIONS

Comprehensive CTA risk score integrating the location, burden and composition of coronary atherosclerosis predicts future cardiac events in patients with suspected CAD.

Incidence of persistent renal dysfunction after contrast enhanced coronary CT angiography in patients with suspected coronary artery disease

Contrast-induced nephropathy (CIN) is a potentially serious complication of contrast agents used in computed tomography angiography (CTA). The aim of this study was to evaluate whether persistent renal dysfunction occurs in patients undergoing coronary CTA for suspected stable coronary artery disease (CAD). From a cohort of 957 patients undergone coronary CTA, we identified 402 patients with plasma creatinine levels collected before and within 6 months after CTA. According to the definition of CIN, patients with a ≥25 % increase in plasma creatinine after CTA were evaluated. The post-CTA measurements in 402 patients (195 men, age 62.9 ± 9.3 years) were performed at a median of 99 days after CTA. On average, there was no change in plasma creatinine level between the pre- and post-CTA measurements (75.8 ± 16.0 and 75.7 ± 16.4 µmol/L, respectively; P = 0.63) but both increases and decreases were commonly detected. Fourteen (3.5 %) patients had a ≥25 % increase in plasma creatinine levels after CTA. A more detailed evaluation of these patients revealed that in 4 patients the increase was explained by other morbidities, whereas in 9 patients the creatinine level returned to the previous levels at later follow-up (median time to normalization: 311 days). Only in 1 (0.2 %) remaining patient, there was a persistent increase in plasma creatinine level, possibly related to the iodine contrast agent exposure. Alterations in plasma creatinine concentration occur frequently. Persistent renal dysfunction attributable to iodine contrast agent exposure is rare in patients referred to coronary CTA for suspected CAD.

Follow-up of 15 children with severe ROP 1987-1989

Between 1987-89 fifteen premature infants with severe retinopathy of prematurity (ROP), at the age of ten months or less, were admitted as outpatients to the Department of Ophthalmology at the Orebro Medical Center Hospital. Initial examination of the infants showed that 6 eyes had stage 3+, 3 eyes had stage 4B and 21 eyes had stage 5 ROP. All 15 infants were born at gestational week 24-28 (mean value 26) and had a birth weight between 600 and 1310 g (mean 907 g). For stage 3+ cryotherapy was performed. For stage 4B and 5 buckling procedure and vitreous surgery was performed in an attempt to re-attach the retina. The children were followed 2-5.5 years. Postoperatively, the retinas of all eyes in stage 3+ and 4B were attached. Four retinas out of seventeen stage 5 eyes were later found to be centrally re-attached. One eye with stage 3+ and four eyes with stage 5 were not treated at all. At follow-up of stage 3+ and 4B, visual acuity was measurable in all eyes; in stage 5 only two out of four eyes with anatomically reattached retinas had perception of light.

Visually impairing ROP in children born in Sweden 1975-89

Among all children registered at the two educational resource centres in Sweden for visually impaired, we found 61 children with ROP causing their visual dysfunction, born 1975-89. Six children had a birthweight exceeding 1460 g, four of these were educationally blind. Sixty children had a gestational age of 30 weeks or less, one child had a gestational age of 31 weeks. Forty-one children had a visual acuity < or = 0.05 while 20 had visual acuity of 0.06-0.3 in the best eye. Twenty-four children had additional handicaps. Seven blind children had developed autistic features. Vitreoretinal surgery had been performed in 27 children. When the retina preoperatively was totally detached surgery failed to restore useful vision. We conclude that it is safer to define the risk group for ROP by gestational age than by birthweight. If the retina already is totally detached it seems advisable to refrain from vitreoretinal surgery.

Phenotypic expression of autosomal dominant retinitis pigmentosa in a Swedish family expressing a Phe-211-Leu variant of peripherin/RDS

PURPOSE

To characterize the clinical phenotype, with emphasis on electrophysiology, of members of a Swedish family with autosomal dominant retinitis pigmentosa due to a novel mutation, F211L, in the peripherin/RDS gene.

METHODS

Nine patients with autosomal dominant retinitis pigmentosa and two healthy family members underwent a full clinical evaluation including kinetic visual field testing, measurement of dark adaptation threshold, and full-field electroretinography. Blood samples were collected and DNA analysis was performed using denaturing gradient gel electrophoresis (DGGE).

RESULTS

The grandfather, six of seven siblings from the middle generation, and two young boys carried the mutation F211L in the peripherin/RDS gene. The mutation segregated with the clinical presentation of disease. Fundus examination revealed mainly macular atrophy. All assessed parameters of retinal function (visual acuity, dark adaptation threshold, visual fields, and full-field electroretinograms) demonstrated a successive reduction with increasing age. Full-field electroretinograms showed a diminished rod response in all affected individuals and a reduction of the cone b-wave amplitudes with increasing age, indicating retinitis pigmentosa. In the affected family members, the disease seems to progress at a similar rate with increasing age.

CONCLUSIONS

The peripherin/RDS gene mutation F211L is associated with a clinical phenotype and includes early loss of rod function and successive reduction of cone function with increasing age, but impressively well-preserved visual acuity and visual fields in young and middle-aged patients and moderately reduced vision in the old patient. Compared to previously described phenotypes segregating with mutations in the peripherin/RDS gene, the present family demonstrates a more benign clinical phenotype, which is concordant within the family.

Severe retinopathy of prematurity in infants from the southern regions of Sweden

We studied children born in 1986-1989 with severe retinopathy of prematurity (ROP) defined as stage 3 "plus" or more. Sixteen children from the southern and central areas of Sweden were identified and 15 of these were referred to Orebro Medical Center Hospital for surgical treatment of ROP. The incidence of severe ROP was estimated as 0.8 per 10,000 newborns per year. All children were born before 29 weeks' gestation and weighed less than 1310 g; they also needed ventilatory support for a long time. The overall neonatal morbidity was high. A model for eye examination in premature newborns is suggested.