Impact of stress myocardial blood flow as an important predictor for major adverse cardiac and cerebrovascular event in hemodialysis patients, even in patients without myocardial perfusion abnormality

Background

In the clinical setting, ischemic heart disease (IHD) is a major problem not only in general patients but also in regular hemodialysis (HD) patients. Positron emission tomography (PET) is becoming a reliable modality for detecting coronary artery disease. Of course, PET illustrates myocardial perfusion (MP), PET also measures myocardial blood flow (MBF) directly. We have reported stress MBF is an independent predictor in HD population. Although some prior studies show CFR is an independent predictor for their prognosis in patients without MP abnormality, there is limited data about the predictability of stress MBF in HD patients without MP abnormality.

Methods

A total 438 of HD patients who undergone 13NH3PET for suspected IHD were enrolled. All patients were undergone13NH3PET at Nagoya Radiological Diagnosis Foundation. After we excluded patients whose summed stress score (SSS) <4, we identified 182 eligible patients. Patients were divided into two group according to the median value of CFR levels; low stress MBF group (≤2.56) and high stress MBF group (>2.56). We followed up them up to 4.2 years (median 2.4 years) and collected their data. We evaluated their major adverse cardiac cerebrovascular event. We performed Kaplan-Meyer analysis and multivariable cox regression models. Furthermore, we evaluated the incremental value with C-index, net reclassification improvement (NRI) and integrated discrimination improvement (IDI) when CFR added into a model with established risk factors.

Result

There were intergroup difference in baseline characteristics: age, gender, prior CVD and diabetes. Kaplan-Meyer analysis shows statistically intergroup difference [log rank p=0.013, hazard ratio (HR) 0.413, 95% confidential interval (CI) 0.220–0.775]. Multivariable cox regression model for MACCE shows CFR is an independent risk factor (p=0.004, HR 0.311, 95% CI 0.137–0.684). As regarding model discrimination, all of C-index (0.832 vs 0.796, p=0.15), NRI (0.513, p=0.008) and IDI (0.032, p=0.033) were greatest in a predicting model with established risk factors plus stress MBF.

Conclusion

The low stress MBF group has poor prognosis in MACCE comparing to the high stress MBF group. Stress MBF is an independent risk factor for MACCE. Adding stress MBF on conventional risk factors could more accurately predict MACCE in HD patients, even in patients without MP abnormality.

Funding Acknowledgement

Type of funding source: None

Diabetes and hemodialysis are important factor for decrease coronary flow reserve even in the patients with normal myocardial perfusion

Background

In clinical setting, patients with traditional coronary risk factors are at high risk for coronary artery disease (CAD). Such patients who complain chest discomfort are usually performed nuclear myocardial perfusion (MP) test. We sometimes find patients whose PET result shows normal MP and abnormal coronary flow reserve (CFR). However, there are limited data about the predictors for decreased CFR. In the view of describe above, we have investigated the parameters for decreased CFR in the patients without MP abnormality.

Methods and results

From 20th April 2013 to 21st December 2018, we performed 2,930 13N- ammonia PET for suspected CAD. After excluding the follows; 966 patients with repeated test, 54 patients with incomplete data, one patient missed, we investigated 1,909 eligible patients' data. We performed least square to identify the factors decreased CFR. Hemodialysis (HD), age, prior revascularization, diabetes (DM) and body mass index (BMI) were independent risk factor for decreased CFR in all population. On the other hand, HD, age, DM, hypertension and BMI were independent risk factor for decreasing CFR in patients without MP abnormality. According to the result of least square methods, we classified all patients into four groups; without DM/ without HD group, with DM/ without HD group, without DM/ with HD group and with DM/ with HD group. The value of CFR in each group were as follows: without DM/ without HD group (median, 1st quartile-3rd quartile; 2.88, 2.21–3.52), with DM/ without HD group (2.65, 2.00–3.38), without DM/ with HD group (2.29, 1.67–2.95) and with DM/ with HD group (1.97, 1.43–2.68). There were statistically significant intergroup differences. The value of CFR in the patients without MP abnormality were as follows: without DM/ without HD group (3.04, 2.47–3.65), with DM/ without HD group (2.98, 2.40–3.61), without DM/ with HD group (2.52, 2.10–3.08) and with DM/ with HD group (2.38, 1.86–2.97). Even in the patients without MP abnormality, there were also statistically significant intergroup differences.

Conclusion

According to our 13N-ammonia PET data analysis, DM and HD were important and independent factors for decreased CFR. Even in the patients without MP abnormality, DM and HD were important factor for decreased CFR.

Funding Acknowledgement

Type of funding source: None

P6240The impact of stress myocardial blood flow as a very strong predictor for all-cause mortality, cardiovascular mortality and adverse cardiac and cerebrovascular event in hemodialysis population

Background

In the clinical setting, ischemic heart disease (IHD) is a major problem not only in general patients but also in regular hemodialysis (HD) patients. 13ammonia positron emission tomography (13NH3PET) is an established and excellent diagnostic device for IHD. Although coronary flow reserve is the most important index in IHD diagnosis, there are limited data about stress myocardial blood flow (MBF). We investigated the prognosis predictability of stress MBF in all-cause mortality, cardiovascular (CV) mortality and adverse cardiac and cerebrovascular event (MACCE).

Methods and results

A total 438 of HD patients who undergone 13NH3PET for suspected IHD were enrolled. 29 cases were excluded due to revascularization therapy in 60 days. In total we collected 409 eligible cases. All patients were undergone13NH3PET at Nagoya Radiological Diagnosis Foundation. Patients were divided into two group according to the median value of stress MBF levels; low stress MBF group (<2.12) and high stress MBF group (≥2.12). We followed up them up to 4.2 years (median 2.4 years) and collected their data. We evaluated their all-cause mortality, CV mortality and MACCE. Kaplan-Meyer analysis shows that intergroup difference in all-cause mortality (log rank p=0.001, hazard ratio [HR] 0.411, 95% confident interval [CI] 0.261–0.632), CV mortality (log rank p=0.002, HR 0.324, 95% CI 0.157–0.625) and MACCE (log rank p<0.001, HR 0.465, 95% CI 0.324–0.657). Multiple cox analysis that include established risk factors shows CFR is an independent risk factor for all-cause mortality (HR 0.261, 95% CI 0.154–0.442), CV mortality (HR 0.172, 95% CI 0.079–0.374) and MACCE (HR 0.329, 95% CI 0.213–0.503). As a result of the incremental value with C-index, net reclassification improvement (NRI) and integrated discrimination improvement (IDI) when CFR added into a model with established risk factors, each indicator shows adding stress MBF on established risk factors improve the predictability in all-cause mortality, CV mortality and MACCE (all-cause mortality; NRI 0.642, p<0.001, IDI 0.091, p<0.001, CV mortality NRI 0.809, p<0.001, IDI 0.116, p<0.001, MACCE; NRI 0.646, p<0.001, IDI 0.072, p<0.001).

Conclusion

Considering prognosis of HD population, stress MBF is an important and independent predictor for all-cause mortality, CV mortality and MACCE. As a result of our investigation, stress MBF is one of most strong predictors in HD population.

P6243Impact of coronary flow reserve as an important predictor for major adverse cardiac and cerebrovascular event in hemodialysis patients even in patients without myocardial perfusion abnormality

Background

In the clinical setting, ischemic heart disease (IHD) is a major problem not only in general patients but also in regular hemodialysis (HD) patients. 13N-ammonia positron emission tomography (13NH3PET) is an established and excellent diagnostic test for IHD. We have reported about the predictability of coronary flow reserve (CFR) in poor prognosis in HD population. Some prior studies show that low CFR predicts poor prognosis for not only cardiovascular event but also all-cause mortality. Although it is well-known that CFR is an important predictor, there are limited data about CFR of patients without myocardial perfusion (MP) abnormality. We investigated the prognostic predictability of adverse cardiac and cerebrovascular event (MACCE) in HD patients without MP abnormality.

Methods

A total 438 of HD patients who underwent 13NH3PET for suspected IHD were enrolled. All patients were underwent 13NH3PET at our facility. After we excluded patients whose summed stress score (SSS) >3, we identified 182 eligible patients. Patients were divided into two group according to the median value of CFR; low CFR group (≤2.405) and high CFR group (>2.405). We followed up them up to 4.2 years (median 2.4 years) and collected their data. We evaluated their major adverse cardiac cerebrovascular event. We performed Kaplan-Meyer analysis and multivariable cox regression models. Furthermore, we evaluated the incremental value with C-index, net reclassification improvement (NRI) and integrated discrimination improvement (IDI) when CFR added into a model with established risk factors.

Results

There were intergroup difference in baseline characteristics: age, gender, prior CVD and diabetes. Kaplan-Meyer analysis shows statistically intergroup difference [log rank p=0.04, hazard ratio (HR) 0.54, 95% confidential interval (CI) 0.30–0.97]. Multivariable cox regression model for MACCE shows CFR is an independent risk factor (p=0.04, HR 0.54, 95% CI 0.30–0.97). As regarding model discrimination, all of C-index (0.82 vs 0.80, p=0.23), NRI (0.51, p<0.01) and IDI (0.03, p=0.03) were greatest in a predicting model with established risk factors plus CFR.

Conclusions

The low CFR group had poor prognosis in MACCE comparing to the high CFR group. CFR would be an independent risk factor for MACCE. Adding CFR on conventional risk factors could more accurately predict MACCE in HD patients, even in patients without MP abnormality.

Studies on cytotoxic effect of nickel ions on three cultured fibroblasts

Cytotoxicity of Ni ions on three fibroblasts such as L929, Balb/3T3 clone A31 and MC3T3-E1 were examined by cell count (CC) and Neutral Red assay (NR). Three cells were incubated for 6 days in 1 ml DME medium containing Ni ions which ranged from 0 to 2 mM/l. The results clarified that Ni ions had dose-dependent cytotoxicity. L929 possessed the largest TC50 values (the amount of Ni ion that caused 50% cell death or 50% cell viability) of 0.12 mM/l (CC) and 0.32 mM/l (NR), and Balb/3T3 clone A31 had the least values of 0.05 mM/l (CC) and 0.09 mM/l (NR), whilst MC3T3-E1 had the intermediate values of 0.08 mM/l (CC) and 0.15 mM/l (NR). The dissolution of Ni ions from Ni-containing metallic restorations must be lower than these concentration levels so that body tissues might not be severely damaged.