Perioperative Platelet Count Ratio Predicts Long-Term Survival after Left Pancreatectomy and Splenectomy for Pancreatic Adenocarcinoma

BACKGROUND

The value of platelet characteristics as a prognostic factor in patients with pancreatic adenocarcinoma (PDAC) remains unclear.

METHODS

We assessed the prognostic ability of post-splenectomy thrombocytosis in patients who underwent left pancreatectomy for PDAC. Perioperative platelet count ratio (PPR), defined as the ratio between the maximum platelet count during the first five days following surgery and the preoperative level, was assessed in relation to long-term outcomes in patients who underwent left pancreatectomy for PDAC between November 2008 and October 2022.

RESULTS

A comparative cohort of 245 patients who underwent pancreaticoduodenectomy for PDAC was also evaluated. The median PPR among 106 patients who underwent left pancreatectomy was 1.4 (IQR1.1, 1.8). Forty-six had a PPR ≥ 1.5 (median 1.9, IQR1.7, 2.4) and 60 had a PPR < 1.5 (median 1.2, IQR1.0, 1.3). Patients with a PPR ≥ 1.5 had increased median overall survival (OS) compared to patients with a PPR < 1.5 (40 months vs. 20 months, p < 0.001). In multivariate analysis, PPR < 1.5 remained a strong predictor of worse OS (HR 2.24, p = 0.008). Among patients who underwent pancreaticoduodenectomy, the median PPR was 1.1 (IQR1.0, 1.3), which was significantly lower compared to patients who underwent left pancreatectomy (p > 0.001) and did not predict OS.

CONCLUSION

PPR is a biomarker for OS after left pancreatectomy for PDAC. Further studies are warranted to consolidate these findings.

Increased prevalence of colorectal neoplasia in patients with intraductal papillary mucinous neoplasms

BACKGROUND

The association between intraductal papillary mucinous neoplasms (IPMNs) and colorectal cancer (CRC) and polyps is controversial.

OBJECTIVES

To compare the prevalence of CRC and colorectal polyps among patients with IPMN and matched average risk individuals.

METHODS

A match cross-sectional historical study comparing colonoscopy findings of 310 patients with IPMN cysts who underwent at least one colonoscopy examination from 2004 through 2019, with 310 age- and gender-matched average risk participants who underwent a screening colonoscopy. CRC and polyps were assessed in both groups. The prevalence and odds ratio were calculated.

RESULTS

CRC was diagnosed in 16 of 310 patients with IPMN (5.2%), and at least one polyp was detected in 96 patients (31%). The prevalence of CRC was greater among patients with IPMN than in matched individuals [5.2% versus 1.3%, p = 0.012, prevalence odds ratio (POR) 4, confidence interval (CI) 1.29-16.44]. The overall prevalence of polyps was not higher among patients with IPMN than in matched individuals (31% versus 26.8%, p = 0.291, POR 1.22, CI 0.85-1.76). However, the prevalence of colorectal adenomas with high-grade dysplasia was higher in patients with IPMN than in matched individuals (4.2% versus 1%, p = 0.02, POR 4.33, CI, 1.19-23.7). The prevalence of large polyps (i.e. more than 20 mm in size) was also greater in patients with IPMN than in matched individuals (6.1% versus 1.9%, p = 0.011, POR 3.6, CI, 1.29-12.40).

CONCLUSION

Patients with IPMN have a significantly higher prevalence of CRC and advanced polyps than the average risk population. In view of our findings, we suggest that once the diagnosis of IPMN is made, special consideration of CRC should be undertaken.

Noninvasive unipolar electrogram T-wave upslope is an accurate marker of local refractoriness in explanted hearts with drug-induced repolarization dispersion

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): French National Research Agency Matthijs Cluitmans is supported by a Veni grant from the Netherlands Organization for Scientific Research

Background

The relationship between T-wave morphology in local unipolar electrograms (UEGs) as mapped with noninvasive electrocardiographic imaging (ECGI) and local repolarization time (RT) has not been validated in pronounced RT dispersion.

Purpose

To study the time of upslope of the T-wave (Tup) in epicardial UEGs mapped with ECGI as a marker of time of local refractoriness (trefr, a surrogate for RT) in intact hearts with RT dispersion.

Methods

Six pig hearts were Langendorff-perfused with selective perfusion of the LAD artery and submersed in a torso-shaped tank containing 256 electrodes on the torso surface (panel A). RT was prolonged in the non-LAD regions by infusing dofetilide (‘Dof’) and shortened in the LAD region using pinacidil (‘Pin’). Tup was determined in both invasive UEGs (recorded with epicardial electrodes) and in noninvasive UEGs (reconstructed with ECGI). Programmed stimulation was used to determine trefr, defined as the shortest coupling interval with capture. Both metrics were determined relative to the common pacing spike.

Results

In all six hearts, selective dofetilide and pinacidil infusion resulted in delayed trefr and Tup in the non-LAD region, and shortened invasive trefr and noninvasive Tup in the LAD region, respectively (panel B and C). Over all 59 observations, Tup showed high agreement with trefr (values close to line of identity, panel D) with strong correlation (r = 0.91). This finding was independent of T-wave polarity (positive, negative or biphasic).

Conclusion

The moment of steepest upslope of the T-wave in a noninvasively reconstructed UEG accurately reflects end of local refractoriness in intact hearts, in case of pronounced RT dispersion. Under these circumstances, when local RT is defined by moment of re-excitability (allowing to link it to conduction block and re-entry), ECGI T-wave upslope can be taken as a truthful marker for local RT. Abstract Figure. Results

A novel trigger-substrate mechanism based on clinically concealed repolarization abnormalities underlies idiopathic ventricular fibrillation

Background

Sudden cardiac arrest (SCA) is most often due to ventricular fibrillation (VF). When no cause is found during diagnostic follow-up, fibrillation is classified as idiopathic (iVF). We hypothesize that a critical functional substrate-trigger interaction underlies iVF.

Purpose

To study electrophysiological triggers and substrate for iVF in a clinical cohort; and seek mechanistic explanations in explanted pig hearts and computer models mimicking trigger-substrate interactions.

Methods

Repolarization time (RT) isochrones on the epicardium were studied with electrocardiographic imaging (ECGI) in patients with iVF, patients with frequent monomorphic premature ventricular complexes (fmPVC) but no structural disease or SCA, and controls without cardiovascular disease.

RT gradients were created in explanted, Langendorff-perfused pig hearts by local infusion of dofetilide (“dof”, 250 nM, delaying RT) and pinacidil (“pin”, 30 μM, shortening RT) in adjacent regions of the heart. Arrhythmia inducibility was tested by programmed stimulation (8 atrial stimuli [S1] followed by one ventricular stimulus [S2] paced at regions of early or late RT).

A computational ventricular monodomain model was used to study the location-dependency of trigger-substrate interaction; RT gradients were created by local changes in potassium channel conductance.

Results

Although QTc values were similar, iVF survivors (n=11) displayed significantly steeper RT gradients than controls (n=10) or fmPVC individuals (n=7): 269±111 vs 179±40 vs 171±76 ms/cm respectively (panel A). Unipolar electrograms (EGMs) at the gradients displayed a change in polarity of the local T wave (B). In iVF, PVCs originated more often from regions with early RT than in fmPVC individuals (yellow circles in A; 64% vs 14%).

In the explanted hearts (C), drug infusion resulted in similar RT gradients and polarity changes of EGM T waves (D-E). VF inducibility by pacing of the early RT region (D) increased significantly with steeper RT gradients (baseline: 3/6 hearts inducible, dof+pin: 3/3). Pacing of late RT regions (E) did not induce arrhythmias in baseline (0/6) nor with RT gradients (0/3). For similar pacing intervals at the early RT region, the 12-lead ECG R-on-T morphology was similar but VF only occurred in the presence of RT gradients (F).

In the computer model, the number of inducible pacing intervals critically depended on the stimulus location (G).

Conclusion

Combined, these results demonstrate that R-on-T superposition per se is insufficient to explain arrhythmogenesis. Rather, not only the temporal coupling interval but also the spatial origin of PVCs in relationship to the degree of local repolarization abnormalities are critical elements. In iVF, a substrate of RT gradients (panel H1) with triggers from early RT regions (H2) precipitate reentry (H3). Noninvasive ECGI can uncover these substrate and trigger characteristics in (at least a subset of) iVF survivors.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Netherlands Organization for Scientific Research Veni grant TTW 16772, French National Research Agency (ANR-10-IAHU04-LIRYC)

Polycaprolactone/glass bioabsorbable implant in a rabbit humerus fracture model

Research in improved materials and methods for internal fixation has centered on internal fixators made of bioabsorbable materials such as polylactic acid, polyglycolic acid, and polyparadioxanone. These materials have two problems: the first is a postoperative complication related to a delayed inflammatory response; and the second is low strength characteristics. An alternative material developed to alleviate these problems is a composite of phosphate glass fibers embedded in the polymer polycaprolactone, referred to as PCL. In this study, intramedullary pins made of PCL were compared to stainless steel pins in a rabbit humerus osteotomy model. Specimens were harvested at 0, 6, and 12 weeks postoperatively, radiographs and mechanical testing to failure were performed at each time interval, and tissue was examined microscopically at 6 and 12 weeks. Histologic results showed PCL pins to be well tolerated with minimal inflammation around the pin. Mechanical testing revealed the PCL fixation to be weaker initially than the stainless steel fixation. There was significant stress shielding of stainless-steel-healed rabbit humeri when compared to the PCL/bone humeri. All osteotomies immobilized with PCL healed with abundant periosteal callus production.

Mechanical behavior of mandibular continuity defects reconstructed using combinations of hydroxylapatite and autogenous bone

The purpose of this investigation was to determine the mechanical behavior of primate (Macaca mulatta) mandibles with continuity defects reconstructed using varying ratios of an alloplastic hydroxylapatite (HA) implant material mixed with autogenous bone (AB). The defects were allowed to heal for 6 and 18 months before killing the animals and mechanical testing. Each animal had one side of the mandible restored with 100% AB as control. The fracture strength and section modulus of the opposite side of the mandible, containing the test ratio of HA-AB, were directly compared with the mechanical behavior of the control side. The fracture strength and section modulus were evaluated by a cantilever type of mechanical test that took into account the anisotropic, viscoelastic, and geometric nature of the mandible. The type of bone and tissue at the fracture site was examined by scanning electron microscopy and a direct correlation between the amount of bone and/or fibrous tissue growth around the HA implant material and the fracture strength and section modulus values was established. The average fracture strength of the AB graft sites at 18 months was 9,975 +/- 4,300 psi, with ratios of 25:75 and 50:50 HA-AB giving test results approaching those of the AB graft sites.

A randomized study of cyclosporine with and without prednisone in renal allograft recipients. Canadian Transplant Group

Sixty-nine patients receiving Cs after cadaveric or LRD renal transplants were randomly allocated to receive prednisone or no prednisone beginning on the day of transplant. There were 36 in the prednisone group and 33 in the group assigned to no prednisone. Of these latter, only seven (21%) never received prednisone and an additional four had one short course for rejection episodes (11%). Of the remaining 22 who were placed on continuous steroids, only 12 met rejection criteria and either some or all of the remainder probably had Cs nephrotoxicity. The patient and graft survival were better but not statistically so in the no-prednisone group (97% v 89%) and (88% v 78%), and the number of infections was only half that of the prednisone-treated group (22% v 42%). A policy of withholding steroids except for rejection episodes does not prejudice graft or patient survival in Cs-treated patients.

Vascular retinopathy in migraine

After years of episodic monocular visual loss, two migraineurs suffered sudden, persisting loss of vision from retinal vascular occlusion. One was a 34-year-old woman with systemic lupus erythematosus who showed abnormalities of the cilioretinal arterial and retinal venous circulations. The other was a 62-year-old man with hypertension and arteriosclerosis who had a central retinal vein occlusion. Persisting monocular visual loss is a rare consequence of migraine. Our cases suggest a role for venous lesions. Occlusion of retinal vessels in some migraineurs may result from the synergistic effect of another vascular disorder with the migraine.

Neovascular glaucoma and carotid artery obstructive disease

Carotid artery obstructive disease, although infrequently diagnosed as a primary or contributing cause of neovascular glaucoma, can produce distinctive characteristics. Decreased perfusion of the ciliary body may decrease aqueous humor production. As a result, such eyes with neovascular glaucoma may occasionally be normotensive or even hypotensive. Fluorescein angiography may show an increased arm-to-retina time and leakage from the major retinal arterioles. Panretinal photocoagulation may not eliminate the anterior segment neovascularization because of anterior segment ischemia. Endarterectomy can significantly increase intraocular pressure as perfusion to the ciliary body returns to normal. These characteristics were found in two patients, a 67-year-old woman and a 49-year-old man, with diabetes and hypertension. In both cases cyclocryotherapy significantly reduced the intraocular pressure and the rubeosis iridis regressed.

Downbeat nystagmus. Long-term therapy with moderate-dose lithium carbonate

Downbeat nystagmus developed in a 67-year-old hypomagnesemic woman while she was receiving lithium carbonate for depression. This nystagmus abated each time lithium carbonate therapy was withdrawn, and no alternative causes of nystagmus were demonstrated. However, this nystagmus occurred despite serum lithium carbonate levels in the nontoxic range. Total-body magnesium deficiency may have enhanced the toxic effect of lithium carbonate on cerebellomedullary connections.

Foster-Kennedy syndrome caused by solitary intracranial plasmacytoma

The first case of typical Foster-Kennedy syndrome, including decreased olfaction of the side of the optic atrophy due to a primary solitary intracranial extraskeletal plasmacytoma, is reported. Its appearance on a computed tomography scan was compatible with a meningioma or subdural hematoma. The patient demonstrated a chronic, corticosteroid-sensitive, relapsing optic neuropathy associated with an elevated sedimentation rate and a monoclonal gammopathy. The diagnosis, treatment, and prognosis of such tumors are reviewed.

Optimized graphical analysis of Gaussian and lognormal assumptions for intraocular and vascular pressure distributions

The design of optimized histogram and probability graphs needed to detect a lognormal distribution in surveys of intraocular pressure (IOP), mean ophthalmic arterial pressure (OAP) and mean ocular perfusion pressure (OPP) is described. Applications are demonstrated in a sample of 58 normal adult eyes. A lognormal distribution was found for IOP and for OAP and OPP estimates obtained with a noncontact noncompressive method. Conversely, the absence of an identifiable linear distribution for OAP and OPP estimates obtained with compression ophthalmodynamometry was noteworthy. The implications of lognormality for definitions of a normal range and for correlations involving IOP, OAP and OPP data are briefly discussed.