Risk stratification and prognostic value of CMR in DCM; parametric mapping and GLS- value beyond EF and LGE?

Funding Acknowledgements

Type of funding sources: Private company. Main funding source(s): Dr Pamela Brown was suppoerted by funding from Alliance Medical.

Background; Arrhythmia risk stratification and device implantation in dilated cardiomyopathy (DCM) poses significant challenges and as demonstrated by the DANISH trial appears to have reached the asymptote of clinical efficacy. A body of evidence now demonstrates that risk stratification of and device selection for DCM patients may be enhanced by inclusion of patients" LGE-status. Furthermore, it has been suggested that CMR based parametric mapping and strain analysis may further advance risk stratification.

Methods; 703 patients with DCM undergoing clinically indicated CMR scans and prospectively enrolled into the UHSM-CMR study (NCT02326324) between 03/2015-12/2018 were analysed. Multivariable Cox proportional hazard models and Youden index driven C-statistics were used to assess additive prognostic value of GLS, T1 and ECV mapping on the combined endpoint of cardiovascular death, cardiac transplantation, LVAD  insertion  or hospitalisation for heart failure in models incorporating NHYA class, EF and LGE status. Additionally. the value of GLS, T1, and ECV on predicting significant arrhythmic events (SAV) (ventricular arrhythmia (VA), resuscitated cardiac arrest (rCA) or sudden cardiac death (SCD)) was assessed.

Results; Patients (mean age 59, 66% male, 60% ≥NYHA II, mean EF 42%, mean GLS -12%, mean ECV 27%) were on good medical therapy (beta blocker 74%%, ACE 79%, MRA 38%, Entresto 5%, CRT 23%). Mean follow-up was 21 months; the combined endpoint occurred in 34 patients (5%). On univariate analysis NYHA class (HR 2.44 (1.67-3.57), p < 0.001), ECV (HR 1.14 (1.05-1.22), p < 0.001), GLS% (HR 1.14 (1.07-1.21) p < 0.001,) T1 (HR 1.06 (1.005-1.1), p = 0.03), RVEF (HR 0.95 (0.93-0.98), p < 0.001), LVEF (HR 0.92 (0.9-0.95), p < 0.001) were all significantly associated with outcome. On multivariate analysis only EF and NYHA class was associated with outcome.

SAV occurred as the first manifestation of disease or during follow up in 27 patients (4%). At univariate analysis LGE, ECV, GLS, EF and NYHA class were all associated with SAV. However, on multivariable analysis only EF, LGE  and ECV (HR 1.11 (1.01-1.22), p = 0.03) but not GLS remained independently predictive in a model already incorporating EF, NYHA and LGE.

Conclusion

Optimally treated DCM populations have very low event rates. CMR based assessment of fibrosis status/burden with both LGE and ECV assessment has the potential to enhance patient selection for ICD therapy. Whilst GLS is increasingly recognised as a sensitive imaging biomarker of early disease detection it provides no additive value,  likely because of it’s high co-linearity with EF, in models already containing EF, NYHA class and LGE status.

Variations in paranasal sinus anatomy: implications for the pathophysiology of chronic rhinosinusitis and safety of endoscopic sinus surgery

OBJECTIVES

To study the radiologic anatomy of the paranasal sinuses in patients with and without chronic rhinosinusitis to assess whether anatomic variations are associated with disease pathology, and to identify those variants that may impact operative safety.

SETTING

Tertiary referral otolaryngology unit.

MAIN OUTCOME MEASURES

Incidence and nature of anatomic variants with potential impact on operative safety, and the presence or absence of sinus mucosal disease and its correlation with anatomic variants with a potential impact on mucociliary clearance.

METHODS

We reviewed 278 computed tomographic scans from patients with rhinosinusitis symptoms to investigate anatomic variations that may predispose to sinusitis or impact on operative safety. The incidence of variants with potential impact on sinus drainage was compared between patients with and without sinus mucosal disease with logistic regression.

RESULTS

A closed osteomeatal complex was identified in 148 patients (53%), followed by concha bullosa in 98 patients (35%). Closed osteomeatal complex and nasal polyposis were independent risk factors for sinus mucosal disease. Anatomic variants with a potential impact on operative safety included anterior clinoid process pneumatization (18%), infraorbital ethmoid cell (12%), sphenomaxillary plate (11%), and supraorbital recess (6%). In 92% of patients, the level difference between the roof of the ethmoid cavity and the cribriform plate was Keros I.

CONCLUSIONS

Bony anatomic variants do not increase the risk of sinus mucosal disease. However, anatomic variants with a potential impact on operative safety occur frequently and need to be specifically sought as part of preoperative evaluation.

The range and nature of sleep dysfunction in untreated Parkinson's disease (PD). A comparative controlled clinical study using the Parkinson's disease sleep scale and selective polysomnography

In this study we have explored the nature and range of sleep dysfunction that occurs in untreated Parkinson's disease (PD) comparing data obtained from the use of the Parkinson's disease sleep scale (PDSS) in an untreated PD patient group compared to advanced PD and healthy controls. 25 untreated (drug-naive, DNPD) PD patients (mean age 66.9 years, range 53-80, 18 males) completed the validated Parkinson's disease sleep scale (PDSS), mean duration of PD was 2.1 years (1-10, up to 4 years in all except one patient with tremulous PD reporting tremor duration of 10 years) and mean Hoehn and Yahr score 1.9 (1-3). Data were compared to 34 advanced PD (mean age 70.2 years, range 51-88, 23 male), mean duration of PD 11 years (range 4-22), mean Hoehn and Yahr score 3.4 (3-5) and PDSS data obtained from 131 healthy controls (mean age 66.6 years, range 50-93, 56 males). Total PDSS scores and PDSS sub-items, except PDSS item 2, were highly significantly different (p<0.001) between DNPD, advanced PD and controls. Controls reported higher mean PDSS scores than both groups of patients, and advanced cases reported lower (mean+/-S.D.) PDSS scores (86.95+/-20.78) than drug-naive (105.72+/-21.5) (p<0.001). Logistic regression analysis showed that items PDSS8 (nocturia), PDSS11 (cramps), PDSS12 (dystonia), PDSS13 (tremor), and PDSS15 (daytime somnolence) were significantly impaired in DNPD compared to controls while PDSS7 (nighttime hallucinations) additionally separated advanced PD from DNPD. In a subgroup of 11 advanced PD cases (mean age 62 years, range=49-84 years, mean Hoehn and Yahr score 2.5, range=1-3) with high Epworth Sleepiness Scale (ESS) scores (mean 14.5), low item 15 PDSS score (mean 4.7) and complaints of severe daytime sleepiness, underwent detailed overnight polysomnography (PSG) studies, all showing abnormal sleep patterns. We conclude that nocturia, nighttime cramps, dystonia, tremor and daytime somnolence seem to be the important nocturnal disabilities in DNPD and some of these symptoms may be reminiscent of "off" period related symptoms even though patients are untreated. Furthermore, polysomnography in "sleepy" PD patients may help diagnose unrecognised conditions such as periodic limb movement of sleep (PLMS), obstructive sleep apnoea (OSA) and REM Sleep Behaviour Disorder.

Dichloroacetate reduces diaphragmatic lactate formation but impairs respiratory performance

Previous studies have found that administration of dichloroacetate (DCA), an agent that reduces lactic acid generation, increases limb muscle endurance. The purpose of the present study was to determine if this agent also improves respiratory muscle performance. To examine this issue, we determined the effect of DCA administration on the response to application of a large inspiratory resistive load (32,000 cm H(2)O/L/s) in unanesthetized decerebrate rats. Studies were carried out in four groups of animals: saline unloaded, DCA unloaded, saline loaded, and DCA loaded. DCA was administered as 100 mg/kg, given intravenously over 30 min, prior to respiratory loading. We found that diaphragm lactate levels were higher in saline-treated loaded animals than in unloaded controls and that DCA administration prevented loading-induced increases in diaphragm lactate (p < 0.001). DCA-treated animals tolerated loading poorly, however, with a more rapid reduction in diaphragm pressure generation and a shorter time to respiratory arrest (42 +/- 3 min) than for saline-treated animals (57 +/- 3 min, p < 0.01). These data indicate that DCA administration decreases the tolerance to loaded breathing despite reductions in diaphragm lactate concentrations. We speculate that suppression of lactate formation by DCA may impair metabolic regulation within the diaphragm during resistive loaded breathing.

Effects produced by infusion of a free radical-generating solution into the diaphragm

Although studies have examined the susceptibility and pattern of injury induced by infusion of free radical-generating solutions into a number of vital organs, no such investigation has been performed for the diaphragm. The purpose of the present study was to examine the susceptibility of the diaphragm to damage by a free radical-generating solution (iron-ADP complexes). Studies were performed using an in situ canine diaphragmatic strip preparation in which the phrenic artery supplying the strip was cannulated and perfused with blood from the ipsilateral femoral artery. Four groups of studies were performed: (1) a group in which saline was infused into the arterial supply of the diaphragm for 15 min; (2) a group in which a solution of iron-ADP was infused; (3) a group in which both iron-ADP and superoxide dismutase (SOD), a free radical scavenger, were infused; and (4) a group given iron-ADP and denatured SOD. Strip tension and blood flow were monitored during electrically induced diaphragmatic contractions for 15 min before intraphrenic infusions, during the period of infusions, and for 90 min after cessation of infusions. We found that diaphragm tension did not change over time in saline-treated control animals but fell significantly in animals in which iron-ADP was infused. The effects of iron-ADP were largely prevented by concomitant administration of active SOD, but not by denatured SOD. On average, at 90 min after cessation of infusions, tension had fallen to 82 +/- 6, 41 +/- 8, 63 +/- 4, and 28 +/- 9% of its initial value in saline, iron-ADP, iron-ADP/SOD, and iron-ADP/denatured SOD groups, respectively (p < 0.001 for comparison of the four groups, with saline and iron-ADP/SOD groups different from the other two groups). Diaphragm blood flow did not change significantly in any group. These data suggest that free radical-mediated diaphragmatic injury can result in a marked reduction in diaphragm contractility.

Effect of PEG-superoxide dismutase on the diaphragmatic response to endotoxin

Although it is known that endotoxin can induce diaphragmatic dysfunction, the mechanism of this effect is not fully understood. However, because the effects of endotoxin on other tissues appear to be mediated in part by free radicals, the present study sought to determine if free radicals may also contribute to the diaphragmatic dysfunction induced by endotoxin administration. Studies were performed on four groups of hamsters. One group of animals received intraperitoneal injections of endotoxin on the first and second days of study (i.e., 10 and 20 mg/kg, respectively). The second group received saline rather than endotoxin, the third group received both endotoxin and a free radical scavenger, PEG-SOD (2,000 U/kg given intraperitoneally every 12 h on Days 1 and 2), and the fourth group received PEG-SOD alone. All groups were killed on the third study day (i.e., 48 h after the initial injections). Diaphragmatic contractile function was assessed in vitro using muscle strips excised from the costal diaphragms of freshly killed animals; diaphragm samples were also assayed for malondialdehyde (MDA), a commonly used index of free-radical-mediated lipid peroxidation. MDA levels were higher in diaphragms from endotoxin-treated animals than from saline-treated control animals, and the contractility of diaphragm strips from endotoxin-treated animals was reduced when compared with strips from saline-treated control animals. Administration of PEG-SOD prevented MDA formation and contractile dysfunction in endotoxin-treated animals. Diaphragm contractility and MDA levels for animals given PEG-SOD alone were similar to those for saline-treated control animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of acute fasting on diaphragm strength and endurance

The effects of short periods of fasting on diaphragm contractile function remain unclear. The purpose of the present study was (1) to examine the relationship between duration of acute fasting and diaphragm contractile performance, and (2) to assess the effects of fasting on diaphragm glycogen stores and the relationship between changes in diaphragm function and alterations in muscle glycogen stores. Studies were performed on four groups of Syrian hamsters (nine animals in each group). One group served as a control and was allowed to feed normally, whereas the other three groups were fasted for either 1, 2, or 3 days. Diaphragm strips from animals were studied in vitro by measuring tension during electrically induced contractions. Two strips from each animal were studied; one strip was examined with a bath glucose equal to the prevailing blood glucose, and the second was preincubated in a high glucose solution (170 mg/dl) for 20 min. Fasting resulted in reductions in body weight, blood glucose concentrations, diaphragm strength, and diaphragm endurance in strips tested at the prevailing blood glucose levels. These effects were pronounced in animals fasted for 3 days, with little or no change in diaphragm contractility observed in animals fasted for shorter periods. Diaphragm weight, thickness, and glycogen content were unchanged in the fasted animals, as was the weight of the soleus muscle. Preincubation of strips from 3-day-fasted animals in a high glucose medium resulted in a significant increase in diaphragm strip strength and endurance.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of codeine on the sensations elicited by loaded breathing

The present study examined the effect of codeine, a centrally acting opiate, on the respiratory sensations elicited in normal subjects by breathing to exhaustion against externally applied inspiratory threshold loads. Subjects were tested on two separate days following the double-blind, randomized administration of either placebo or codeine (90 mg). The intensity of the sensations of effort and discomfort experienced during two loaded breathing trials (a "high" load that was 73% of the maximum inspiratory pressure (MIP) and a "low" load that was 63% of the MIP) was evaluated using category (Borg) scores on each day of study. To verify that the dosage of codeine administered was sufficient to produce analgesia, we also determined the effect of this dosage on the time that subjects could tolerate immersion of one hand in ice water. Codeine altered neither the perceived effort nor the sense of discomfort associated with breathing against external loads and had no appreciable effect on the time to exhaustion during loaded breathing trials. This dose of codeine did, however, increase the time that ice water immersion could be tolerated and reduced the rate at which the sense of discomfort increased over time during ice water trials. These results indicate that, provided the pressure-time index of respiratory muscle contraction remains constant, analgesic doses of codeine alter neither the sensations elicited by loaded breathing nor the total time that breathing against a fatiguing inspiratory load can be tolerated.