Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

Gonadotrophin-inhibitory hormone receptor expression in the chicken pituitary gland: potential influence of sexual maturation and ovarian steroids

Gonadotrophin-inhibitory hormone (GnIH), a hypothalamic RFamide, has been found to inhibit gonadotrophin secretion from the anterior pituitary gland originally in birds and, subsequently, in mammalian species. The gene encoding a transmembrane receptor for GnIH (GnIHR) was recently identified in the brain, pituitary gland and gonads of song bird, chicken and Japanese quail. The objectives of the present study are to characterise the expression of GnIHR mRNA and protein in the chicken pituitary gland, and to determine whether sexual maturation and gonadal steroids influence pituitary GnIHR mRNA abundance. GnIHR mRNA quantity was found to be significantly higher in diencephalon compared to either anterior pituitary gland or ovaries. GnIHR mRNA quantity was significantly higher in the pituitaries of sexually immature chickens relative to sexually mature chickens. Oestradiol or a combination of oestradiol and progesterone treatment caused a significant decrease in pituitary GnIHR mRNA quantity relative to vehicle controls. GnIHR-immunoreactive (ir) cells were identified in the chicken pituitary gland cephalic and caudal lobes. Furthermore, GnIHR-ir cells were found to be colocalised with luteinising hormone (LH)beta mRNA-, or follicle-stimulating hormone (FSH)beta mRNA-containing cells. GnIH treatment significantly decreased LH release from anterior pituitary gland slices collected from sexually immature, but not from sexually mature chickens. Taken together, GnIHR gene expression is possibly down regulated in response to a surge in circulating oestradiol and progesterone levels as the chicken undergoes sexual maturation to allow gonadotrophin secretion. Furthermore, GnIHR protein expressed in FSHbeta or LHbeta mRNA-containing cells is likely to mediate the inhibitory effect of GnIH on LH and FSH secretion.

Swan-Ganz catheter-induced pulmonary artery pseudoaneurysm formation: three case reports and a review of the literature

The use of Swan-Ganz catheters has increased tremendously since they were first introduced in 1970. Their ability to give vital hemodynamic measurements in critically ill patients makes their use invaluable when providing quality medical care. The formation of pulmonary artery (PA) pseudoaneurysm from a Swan-Ganz catheter-induced perforation of the PA is a rare but potentially fatal complication of Swan-Ganz catheter use. Three case presentations and a review of the literature are presented.

Surgical treatment of carcinoid tumours

Carcinoid tumours are the most common endocrine tumour of the gut comprising 75% of appendicular tumours and a third of ileal tumours. They are also an incidental finding in 1% of post mortems. Carcinoid syndrome however is rare and it is estimated that two cases would appear in a quarter of a million population over a decade. We have reviewed a consecutive series of carcinoid tumours accrued from 1976-1999 in order to further study the natural history of the disease and also to examine the relationship between pathological tumour size, extent of disease and prognosis for each tumour site. In this 19 year period 145 patients were treated for the disorder. The bronchus was the commonest site (35.9%) with appendix (24.8%) and ileal (13.8%) carcinoids comprising the majority of known primaries. Overall midgut carcinoids comprised 40.7% of the series with the carcinoid syndrome present in 20.3%. A significant group was constituted by those patients presenting with metastatic disease and an uncertain site of primary tumour (9.7%). Metastatic disease was not found on presentation or follow up in any patient with a foregut primary tumour less than 2 cm diameter or a midgut primary tumour less than 1 cm diameter; a direct correlation of size and metastases being found above these levels. Overall survival for all groups was 60% at 5 years with the best prognosis being seen in patients with bronchial or appendicular carcinoids. Other clinical features, pathology, extent of disease and prognosis of carcinoid tumour will be discussed along with the role of current management strategies.

Balloon angioplasty or stent placement in patients with azotemic renovascular disease: a retrospective comparison of clinical outcomes

In this study comparing functional outcomes of renal angioplasty alone (PTRA) or angioplasty with stent placement in patients with renal artery stenosis (> or =60%) and renal insufficiency, 69 patients were treated with PTRA or stent placement. After censoring, the PTRA group included 15 patients with a mean age of 75 years, mean serum creatinine (Cr) of 2.9 +/- 1.4 mg/dL, and mean follow-up of 10 months. The stent placement group included 40 patients with a mean age of 71 years, mean Cr of 2.6 +/- 1.2 mg/dL, and mean follow-up of 12 months. Stenting was performed primarily in four cases and after suboptimal angioplasty in the remainder. Benefit was defined as either stabilization (+/-20%) or improvement in serum Cr levels. Technical success was achieved in 16 of 17 (94%) PTRA patients and 55 of 58 (95%) patients receiving stents. Complications included one surgically repaired axillary pseudoaneurysm, one distal stent positioning requiring a second stent, one stent protruding 5 mm into the aorta, two dissections requiring additional stents, one retroperitoneal hematoma, and one intrarenal atheroembolism treated with thrombolysis. Three patients (mean initial Cr 3.9 mg/dL) required hemodialysis within 30 days of stenting. One patient discontinued dialysis after stenting. There were two procedure-related deaths. An overall benefit was seen in 40% of patients after PTRA and 66% of patients after stent placement. For the stent placement and PTRA groups, cumulative clinical benefit was 77% and 80%, respectively, at 3 months; 69% and 64%, respectively, at 6 months; 61% and 41%, respectively, at 12 months; and 48% and 14%, respectively, at 24 months. A 50% loss of cumulative benefit was seen 34 months after stenting and 11.5 months after PTRA. In the stent and PTRA groups, benefit was noted in 77% and 57%, respectively, of patients with an initial Cr of 2.3 or less, 53% and 25%, respectively, of patients with an initial Cr level higher than 2.3, and 44% and 17%, respectively, of patients with an initial Cr level of 3.0 mg/dL or more. For patients with renal insufficiency, renal artery stenting provides superior clinical results compared with PTRA, mostly because late deterioration occurs after PTRA. Outcomes are related to pretreatment serum Cr level.

Value of CT angiography for postoperative assessment of patients with iliac artery aneurysms who have received endovascular grafts

OBJECTIVE

The purpose of the study was to assess the usefulness of CT angiography for follow-up of patients with iliac artery aneurysms who have undergone endovascular treatment.

SUBJECTS AND METHODS

Twelve patients with iliac artery aneurysms (10 true aneurysms and two pseudoaneurysms) were examined with CT angiography within 1 week of receiving transfemorally placed endovascular grafts. All patients underwent follow-up CT angiography from 3 to 30 months (mean, 11 months) later. Follow-up CT angiography at 6 months or later (mean, 14 months) was also available in 10 patients. All studies were obtained after i.v. contrast administration using 3-mm collimation, 1.6-2.0 pitch, 2-mm retrospective reconstruction, and with subsequent three-dimensional rendering and multiplanar reformation. The shape and patency of the graft, perigraft thrombosis, and the size of the aneurysm were assessed.

RESULTS

All grafts remained patent and without deformity. Complete thrombosis of the aneurysm was shown by initial postoperative CT angiography in 11 patients and confirmed by follow-up studies. A single case of a perigraft leak was revealed by CT angiography and confirmed by follow-up angiography. No aneurysm showed change in size at late follow-up.

CONCLUSION

CT angiography is an accurate method for evaluating endovascular devices. CT angiography can be used as a primary technique for follow-up of patients who have undergone endovascular repair of iliac aneurysms.