PRESS survey: PREvention of surgical site infection-a global pan-specialty survey of practice protocol

Background

Surgical site infections (SSI) complicate up to 40% of surgical procedures, leading to increased patient morbidity and mortality. Previous research identified disparities in SSI prevention guidelines and clinical practices across different institutions. The study aims to identify variations in SSI prevention practices within and between specialties and financial systems and provide a representation of existing SSI preventative measures to help improve the standardization of SSI prevention practices.

Methods

This collaborative cross-sectional survey will be aimed at pan-surgical specialties internationally. The study has been designed and will be reported in line with the CROSS and CHERRIES standards. An international study steering committee will design and internally validate the survey in multiple consensus-based rounds. This will be based on SSI prevention measures outlined in the CDC (2017), WHO (2018), NICE (2019), Wounds UK (2020) and the International Surgical Wound Complications Advisory Panel (ISWCAP) guidelines. The questionnaire will include demographics, SSI surveillance, preoperative, peri-operative and postoperative SSI prevention. Data will be collected on participants' surgical specialty, operative grade, of practice and financial healthcare system of practice. The online survey will be designed and disseminated using QualtricsXM Platform™ through national and international surgical colleges and societies, in addition to social media and snowballing. Data collection will be open for 3 months with reminders, and raking will be used to ascertain the sample. Responses will be analyzed, and the chi-square test used to evaluate the impact of SSI prevention variables on responses.

Discussion

Current SSI prevention practice in UK Vascular surgery varies considerably, with little consensus on many measures. Given the inconsistency in guidelines on how to prevent SSIs, there is a need for standardization. This survey will investigate the disparity in SSI preventative measures between different surgical fields and countries.

Serum cobalamin and methylmalonic acid concentrations in juvenile dogs with parvoviral enteritis or other acute enteropathies

BACKGROUND

Low serum cobalamin concentrations have been associated with ileal malabsorption in dogs with chronic enteropathy. Increased serum methylmalonic acid (MMA) concentrations indicate cobalamin deficiency on a cellular level. Few studies have evaluated serum cobalamin concentrations or methylmalonic acid concentrations in juvenile dogs with parvoviral enteritis or nonparvoviral acute enteropathies.

OBJECTIVES

Evaluate serum cobalamin and methylmalonic acid concentrations in juvenile dogs (6 weeks to 10 months old) with parvoviral enteritis or nonparvoviral acute enteropathy.

ANIMALS

Thirty-one juvenile dogs with parvoviral enteritis, 29 dogs with nonparvoviral acute diarrhea (NPVAD), and 40 healthy juvenile control dogs.

METHODS

Single-center, prospective, observational, cross-sectional study. Serum cobalamin and, when sufficient serum was available, MMA concentrations were measured.

RESULTS

Most serum cobalamin concentrations were within the adult reference interval. Serum cobalamin concentrations in healthy dogs (median, 848 ng/L; range, 293-1912 ng/L) were significantly higher than in dogs with parvoviral enteritis (P = .0002; median, 463 ng/L; range, <150-10 000 ng/L) or dogs with NPVAD (P = .02; median, 528 ng/L; range, 160-8998 ng/L). Serum MMA concentrations were not significantly different between groups (healthy dogs: median, 796 nmol/L; range, 427-1933 nmol/L; parvoviral enteritis: median, 858 nmol/L; range, 554-3424 nmol/L; NPVAD: median, 764 nmol/L; range, 392-1222 nmol/L; P = .1).

CONCLUSIONS AND CLINICAL IMPORTANCE

Juvenile dogs with parvoviral enteritis or NPVAD had lower serum cobalamin concentrations than healthy juvenile dogs. However, based on serum MMA concentrations cellular cobalamin deficiency was not apparent.

Resolvin D1 promotes efferocytosis in aging by limiting senescent cell-induced MerTK cleavage

Inflammation-resolution is mediated by the balance between specialized pro-resolving mediators (SPMs) like resolvin D1 (RvD1) and pro-inflammatory factors, like leukotriene B₄ (LTB₄). A key cellular process of inflammation-resolution is efferocytosis. Aging is associated with defective inflammation-resolution and the accumulation of pro-inflammatory senescent cells (SCs). Therefore, understanding mechanism(s) that underpin this impairment is a critical gap. Here, using a model of hind limb ischemia-reperfusion (I/R) remote lung injury, we present evidence that aging is associated with heightened inflammation, impaired SPM:LT ratio, defective efferocytosis, and a decrease in MerTK levels in injured lungs. Treatment with RvD1 mitigated I/R lung injury in aging, promoted efferocytosis, and prevented the decrease of MerTK in injured lungs from old mice. Old MerTK cleavage-resistant mice (MerTK^CR) exhibited less neutrophils or polymorpho nuclear cells infiltration and had improved efferocytosis compared with old WT controls. Mechanistically, macrophages that were treated with conditioned media (CM) from senescent cells had increased MerTK cleavage, impaired efferocytosis, and a defective RvD1:LTB₄ ratio. Macrophages from MerTK^CR mice were resistant to CM-induced efferocytosis defects and had an improved RvD1:LTB₄ ratio. RvD1-stimulated macrophages prevented CM-induced MerTK cleavage and promoted efferocytosis. Together, these data suggest a new mechanism and a potential therapy to promote inflammation-resolution and efferocytosis in aging.

Abstract 002: Resolvin D1 Limits Senescent Cells in Atherosclerosis

Non-resolving inflammation is the underpinning of several prevalent diseases including atherosclerosis. Understanding new mechanisms to promote the resolution of inflammation in atherosclerosis are of interest. Resolution is mediated by resolvins, including Resolvin D1 (RvD1). We recently showed that RvD1 prevents lesional necrosis in Ldlr -/- mice. However, the mechanisms underlying RvD1’s protective actions remain unknown. In this regard, the accumulation of senescent cells (SCs) was recently shown to promote necrotic core formation in Ldlr -/- mice. SCs are harmful because they possess a pro-inflammatory and proteolytic phenotype called the senescence associated secretory phenotype (SASP). Because RvD1 decreased lesional necrosis, we questioned whether RvD1’s actions were through limiting SCs in plaques. First, we found that human symptomatic plaques had significantly less RvD1 and significantly more SCs (quantified by positive p16 INK4A immunofluorescence staining) compared with asymptomatic plaques. To prove causation, we administered RvD1 to Ldlr -/- mice during advanced atherosclerosis and observed a significant decrease in lesional SCs and necrosis compared with vehicle controls. Mechanistically, we found that RvD1 significantly decreased the SASP as well as beta-galactosidase and p16 INK4A in WI-38 senescent cells. Importantly, a major component of the SASP is ADAM17, which is an enzyme that cleaves (and thus inactivates) a critical efferocytosis receptor on macrophages called MerTK. Because SCs are not cleared in plaques we questioned whether the SASP deranges efferocytosis mechanisms via their ability to cleave MerTK on macrophages. To investigate whether MerTK cleavage deranges SC clearance in plaques, we transplanted bone marrow from wild type (WT) or MerTK cleavage resistant (Mertk CR ) mice into Ldlr -/- mice, and quantified the levels of lesional p16 INK4A after 12 weeks of Western Diet feeding. Mertk CR mice had significantly less p16 INK4A levels and smaller necrotic cores compared with WT controls. Overall, we identified new functions for RvD1 and uncovered, for the first time, an endogenous mechanism for SC clearance. Our findings may provide new therapeutic strategies to treat atherosclerosis.

Levels of activated platelet-derived microvesicles in patients with soft tissue sarcoma correlate with an increased risk of venous thromboembolism

Background

Microvesicles are small vesicles expressing specific antigens from their cells of origin. Elevated levels of microvesicles have been shown to be associated with coagulation disorders as well as with different types of malignancies. This study aims to evaluate a possible correlation of different microvesicle subpopulations with a positive history of venous thromboembolism (VTE) in patients with soft tissue sarcoma.

Methods

Annexin V - positive microvesicles, leukocyte (CD45-positive), platelet (CD61-positive), activated platelet (CD62P-, CD63-positive), endothelium-derived (CD62E-positive) and tissue-factor (CD142-positive) microvesicles were identified in the peripheral blood of patients with soft tissue sarcoma (n = 39) and healthy controls (n = 17) using fluorescence-activated cell sorting (FACS).

Results

Both the total amount of Annexin V-positive microvesicles and levels of endothelium-derived (CD62E-positive) microvesicles were shown to decrease significantly after tumor resection (n = 18, p = 0.0395 and p = 0.0109, respectively). Furthermore, the total amount of Annexin V – positive microvesicles as well as leukocyte (CD45-positive) and endothelium-derived (CD62E-positive) microvesicles were significantly higher in patients with grade 3 (G3) soft tissue sarcoma (n = 9) compared to healthy controls (n = 17) (p = 0.0304, p = 0.0254 and p = 0.0357, respectively). Moreover, patients with G3 soft tissue sarcoma (n = 9) presented higher levels of Annexin V-positive and endothelium-derived (CD62E-positive) microvesicles compared to patients with grade 2 (G2) soft tissue sarcoma (n = 8) (p = 0.0483 and p = 0.0045). Patients with grade 1 (G1) soft tissue sarcoma (n = 3) presented with significantly lower levels of platelet (CD61-positive) microvesicles than patients with G3 soft tissue sarcoma (n = 9) (p = 0.0150).

In patients with a positive history of VTE (n = 11), significantly higher levels of activated platelet (CD62P- and CD63-positive) microvesicles (p = 0.0078 and p = 0.0450, respectively) were found compared to patients without a history of VTE (n = 28).

Conclusion

We found significantly higher levels of Annexin V-positive and endothelium-derived (CD62E-positive) microvesicles to be circulating in the peripheral blood of patients with G3 soft tissue sarcoma compared to patients with G2 soft tissue sarcoma. Furthermore, we showed that high counts of activated platelet-derived microvesicles correlate with the occurrence of VTE. Thus, the detection of these microvesicles might be an interesting new tool for early diagnosis of soft tissue sarcoma patients with increased risk for VTE, possibly facilitating VTE prevention by earlier use of thromboprophylaxis.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-017-3515-y) contains supplementary material, which is available to authorized users.

High Rates of Thromboembolic Events in Patients with Germ Cell Cancer Undergoing Cisplatin-Based Polychemotherapy

BACKGROUND

We examined whether or not extended prophylaxis with low molecular weight heparin (LMWH) would significantly reduce thromboembolic event (TEE) rates in germ cell cancer patients undergoing cisplatin-based chemotherapy.

PATIENTS AND METHODS

LMWH prophylaxis was given from the first day of chemotherapy until 21 days after completing the last chemotherapy cycle to 45 out of 93 (48.4%) patients (extended), and to 48 out of 93 (51.6%) patients during their hospitalization only (limited) between January 2008 and December 2013. Patients were analyzed retrospectively for TEEs such as deep vein thrombosis (DVT), pulmonary embolism (PE), myocardial infarction (MI) or peripheral arterial thrombosis.

RESULTS

A total of 22/93 (23.7%) patients experienced 30 TEE during chemotherapy: 12 out of 30 (40%) deep vein thrombosis, 4 out of 30 (13.3%) MI, 10 out of 30 (33.3%) PE and 4 out of 30 peripheral arterial thrombosis (13.3%). TEE rates in both groups did not differ significantly (extended: 26.7 vs. limited: 20.8%).

CONCLUSIONS

The introduction of extended LMWH prophylaxis did not significantly reduce TEE rates in our patient cohort.

[Spindlecell soft tissue tumors of para- and retropharyngeal space: 5 patients, review of literature]

BACKGROUND

The parapharyngeal space (PPR) is poorly accessible to clinical investigation due to its complex anatomy. Neoplasms in this area are rare, become lately symptomatic and are diagnosed in advanced stages. Multiple entities can be differentiated though malignant mesenchymal tumors are uncommon.

PATIENTS

We describe characteristic course of spindle cell soft tissue tumors in PPR based on 5 patients: 2 cases of synovial sarkoma (SyS), 2 cases of malignant peripheral nerve sheath tumor (MPNST) without neurofibromatosis, 1 case of Ektomesenchymoma (EM).

RESULTS

Both patients with SyS showed under multimodal therapy with surgery, chemotherapy and radiotherapy a rapid tumor progression and early pulmonary metastatic disease. The 2 patients with MPNST were free of recurrence after tumor resection and in one case after adjuvant radiotherapy. The patient with EM showed no recurrence after surgery.

CONCLUSION

Since malignant mesenchymal tumors of the PPR are unusual and also not have the typical behavior of metastatic epithelial neoplasms or malignant lymphoma, the diagnosis may be delayed. It is important to think in atypical lesions in PPR of the possibility of a soft tissue tumor and to arrange the necessary diagnostic steps. The imaging of choice of the PPR is the MRI, a staging adapted to the entity is necessary. The histological differentiation by immunohistochemistry and molecular genetics is complex, but is a vital to determine the optimal therapy. Diagnosis and treatment should take place in a specialized center.

Development, validation, and pilot application of a semiquantitative Western blot analysis and an ELISA for bovine adiponectin

Adiponectin is an adipose tissue-derived glycoprotein circulating as highly abundant multimers. It regulates glucose metabolism and insulin sensitivity. In ruminants, valid data about serum concentrations and tissue-specific protein expression are lacking, and we, therefore, aimed to generate a polyclonal antibody against bovine adiponectin to apply it in immunodetection. The specificity of the purified anti-adiponectin antibody was established by Western blot analysis with the use of reducing and denaturing conditions applied to both the purified protein and the bovine serum samples. Besides bovine serum, the applicability of the antibody for immunodetection of adiponectin was confirmed for the supernatant fluid of in vitro-differentiated bovine adipocytes, for protein extracts from bovine adipose tissue, and also in a multispecies comparison: bands comparable in size with monomeric bovine adiponectin were obtained under denaturing conditions in serum of camel, horse, human, mouse, pig, roe deer, and sheep. In addition, when used in immunohistochemistry on bovine adipose tissue sections, a characteristic adipocyte-specific staining pattern was obtained with this antibody. The antibody was used for establishing a semiquantitative Western blot procedure and the development of an ELISA. Both methods were extensively validated and were first applied to characterize the serum adiponectin concentrations in multiparous dairy cows during the transition from pregnancy to lactation, that is, 3 wk before until 5 wk after calving. With both assays a time effect (P = 0.017, P = 0.026, respectively) with lowest values at the day of parturition was observed. We thus established 2 useful tools to validly assess bovine adiponectin at the protein level.

Dietary patterns and survival in German postmenopausal breast cancer survivors

BACKGROUND

Research on the association between dietary patterns and breast cancer survival is very limited.

METHODS

A prospective follow-up study was conducted in Germany, including 2522 postmenopausal breast cancer patients diagnosed in 2001-2005 with available food frequency questionnaire data. Vital status, causes of death, and recurrences were verified through the end of 2009. Principle component factor analysis was used to identify pre-diagnostic dietary patterns. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated with Cox proportional hazards models.

RESULTS

Two major dietary patterns were identified: 'healthy' (high intakes of vegetables, fruits, vegetable oil, sauces/condiments, and soups/bouillons) and 'unhealthy' (high intakes of red meat, processed meat, and deep-frying fat). Increasing consumption of an 'unhealthy' dietary pattern was associated with an increased risk of non-breast cancer mortality (highest vs lowest quartile: HR, 3.69; 95% CI, 1.66-8.17; P-trend <0.001). No associations with breast cancer-specific mortality and breast cancer recurrence were found. The 'healthy' dietary pattern was inversely associated with overall mortality (HR, 0.74; 95% CI, 0.47-1.15; P-trend=0.02) and breast cancer recurrence (HR, 0.71; 95% CI, 0.48-1.06; P-trend=0.02) in stage I-IIIa patients only.

CONCLUSION

Increasing intake of an 'unhealthy' pre-diagnostic dietary pattern may increase the risk of non-breast cancer mortality, whereas increasing intake of a 'healthy' pattern may reduce the risk of overall mortality and breast cancer recurrence.

Estimated enterolignans, lignan-rich foods, and fibre in relation to survival after postmenopausal breast cancer

Background:

Lignans – oestrogenic substances present in various foods – are associated with postmenopausal breast cancer risk, but not much is known regarding their effects on survival.

Methods:

In a follow-up study of 2653 postmenopausal breast cancer patients diagnosed between 2001 and 2005, vital status and causes of death were verified through end of 2009. Hazard ratios (HRs) and 95% confidence intervals (CIs) for estimated enterolignans, lignan-rich foods, and dietary fibre in relation to overall survival (OS) and breast cancer-specific survival (BCSS) were assessed using Cox proportional hazards models stratified by age at diagnosis and adjusted for prognostic/confounding factors.

Results:

Median follow-up time was 6.4 years, and 321 women died, 235 with breast cancer. High estimated enterolactone and enterodiol levels were associated with significantly lower overall mortality (highest quintile, HR=0.60, 95% CI=0.40–0.89, P_Trend=0.02 and HR=0.63, 95% CI=0.42–0.95, P_Trend=0.02, respectively). Fibre intake was also associated with a significantly lower overall mortality. Differentiated by median fibre intake, associations with estimated enterolignans were still evident at low but not high fibre intake. There was no effect modification by oestrogen receptor status and menopausal hormone therapy.

Conclusion:

Postmenopausal breast cancer patients with high estimated enterolignans may have a better survival.

Vitamins are associated with survival in patients with end-stage renal disease: a 4-year prospective study

BACKGROUND

Patients with end-stage renal disease are at high risk from premature death due mainly to cardiovascular disease and infections. Established risk factors do not sufficiently explain this increased mortality. We, therefore, investigated total mortality prospectively in a single-centre study in patients on hemodialysis and assessed the prognostic value of baseline disease status, laboratory variables including emerging risk factors, and the influence of vitamin treatment.

METHODS

Patients (n = 102) were followed-up for 4 years or until death (n = 49). Survival was calculated by the Kaplan-Meier method. Cox-proportional hazards model was used to determine independent predictors of total mortality.

RESULTS

The known risk factors age, baseline clinical atherosclerotic disease, low albumin and increased cardiac troponin T were significantly associated with mortality. Patients who received multivitamins during follow-up had a significantly lower mortality risk than those not receiving this treatment (hazard ratio 0.29, 95% confidence interval 0.15-0.56). These associations remained significant after adjustment for age, cardiovascular disease, albumin and cardiac troponin T at baseline.

CONCLUSIONS

The present study suggests that multivitamin supplementation in patients with end-stage renal disease is closely associated with reduced mortality due to all causes. These observations have to be validated in randomized clinical intervention trials.

Three-dimensional GPR analysis of various Quaternary gravel-bed braided river deposits (southwestern Germany)

Closely spaced (1 m) ground penetrating radar (GPR) profiles were used for a three-dimensional characterization and comparison of glaciofluvial gravel-bed deposits in palaeodischarge zones of the Würmian Rhine glacier (southwestern Germany). Previous sedimentological outcrop investigations revealed three regionally reoccurring architectural styles of gravel bodies. For each of these styles a three-dimensional GPR dataset has been acquired in active gravel pits in order to calibrate the radar profiles with outcrop walls and to analyse, in three dimensions, the depositional elements and their stacking pattern in the subsurface.

The GPR data were interpreted by mapping reflection terminations in order to delineate genetically related units. In particular, radar facies types and radar sequence boundaries were used to define and map depositional elements. Both accretionary and cut-and-fill depositional elements could be identified. Accretionary elements are characterized by horizontally to low-angle inclined (1–3°) and moderately continuous reflections (5–30 m) terminating on flat sequence boundaries; they represent the deposits of gravel sheets and traction carpets. In contrast, cut-and-fill elements are characterized by low to steeply inclined (3–25°), often discontinuous reflections terminating on concave to trough-shaped lower truncation boundaries; these are interpreted as scour-pool fills and small dissection elements (e.g. chutes and lobes).

The three basic architectural styles of gravel bodies can be distinguished on the basis of the size and proportion of cut-and-fill elements mapped within the radar images. One type of gravel body is composed of an amalgamation of large cut-and-fill elements whereas the other two types are dominated by accretionary elements and differ by the proportion of smaller cut-and-fill elements.

The results show that GPR is an adequate technique to illuminate the sedimentary architecture of the various types of gravel bodies. GPR data allow detailed three-dimensional reconstruction of depositional elements and their stacking pattern in the subsurface.

Psychiatric epidemiology of an Indian village. A 19-year replication study

This 1988 study reports the point and lifetime prevalence of psychiatric disorders, using DSM-III-R criteria, of a sample (approximately 25%) of adult members of an Indian village previously studied in 1969. The basic instrument was the Schedule for Affective Disorders and Schizophrenia, augmented by available medical information and administered by experienced psychiatrists. Subjects were interviewed and results were weighed for the age- and sex-distributed population. The results indicated a high point prevalence of alcohol dependence (32.8%), with a lifetime prevalence of 72.8%, among males. The lifetime prevalence of affective disorders among women was also high (36.8%), but less so among men (19.3%). When compared with the DSM-III-R diagnoses of the 1969 study, the point prevalence rates of alcohol dependence and abuse disorders fell from 39% to 21%. Also, fewer subjects were judged to be psychiatrically impaired. Even though the prevalence of psychiatric disorders was lower in the current study, the rates for alcohol disorders and affective disorders were still far higher than those reported in Epidemiologic Catchment Area studies. Alcohol dependence (especially among young men) and affective disorder (among women) were major problems.

Trochanteric fractures treated with the Pugh nail: a study of 270 cases

We report a series of 270 intertrochanteric fractures of the femur which were treated with the Pugh nail in our department. We used it as a standard treatment of intertrochanteric fractures and lateral fractures of the femoral neck. The Pugh nail method is characterized by a simple technique, a low rate of complications, and early ambulation and weight-bearing, which is important for the mostly aged patients (average age: 81 years). 81% of the patients could be ambulized with weight-bearing within two weeks after operation. 79% of them were able to walk by themselves at discharge from hospital. The rate of complications was 17% without urinary infections. Mortality was 16%. Complications and mortality did not depend on the type of fracture but on the age of the patients and on concomitant diseases.

[Bilateral spontaneous rupture of the patellar tendon in systemic lupus erythematosus. A case report and review of the literature]

A rupture of the patella ligament occurs after acute trauma or if there are factors that could have predisposed to the rupture like former injuries or operations of the knee or systemic diseases. If symptoms like loss of active extension, no patella tendon reflex, and a proximally displaced patella in radiograph appear in cases of those diseases, it should be thought of the rare rupture of the patella ligament. It will be treated operatively by suture of the tendon supporting by a wire, applying a cast for six to eight weeks and following physical therapy.

[The use of fibrin tissue adhesive in parenchymal organs of the abdomen. An experimental study in rabbits and dogs (author's transl)]

In rabbits and dogs standardized lesions of the liver, kidney, and spleen were treated by application of human fibrinogen tissue adhesive. In all cases this procedure resulted in a complete control of bleeding as well as a stable and lasting closure of the wounds. During the postoperative observation time of one month, the fibrinogen tissue adhesive was initially infiltrated by leucocytes and macrophages and subsequently resorbed by a granulating tissue, characterized by the early appearance of numerous fibroblasts. Our clinical experience, until now, confirms these promising experimental results.

Mitral regurgitation and characteristic changes in impedance cardiogram

We have noted that the impedance cardiographic waveform of patients with mitral regurgitation may show typical abnormalities not found in other forms of cardiac disease, either valvular or congenital. In order to investigate this we reviewed the impedance cardiograms of all our patients who had also undergone cardiac catheterisation, and selected two groups both of which were inclusive and complete: (1) 22 patients with the diagnosis of normal heart, and (2) 36 patients with the diagnosis of isolated mitral regurgitation. An index was calculated algebraically from the change of impedance (delta L) tracing by adding together the height of the C wave and the height of the nadir of the X descent and subtracting the height of the V wave, that is delta Z index (in units of ohms) = C + X - V. The mean delta Z index for the normal group was 1.64 and for the mitral regurgitation group 0.96 ohms. Similarly, an index was calculated from the first time derivative of the change of impedance (dZ/dt) tracing, that is dZ/dt index (in units of ohms/s) = C' + X' - V'. The mean dZ/dt index for the normal group was 1.32 and for the mitral regurgitation group 0.48 ohms/s. Though there was some overlap of individual points between the two groups, the mean values for both the delta Z index and the dZ/dt index separated the group with mitral regurgitation from the normal group with a high level of statistical significance. We concluded that mitral regurgitation might be associated with a characteristic abnormality of the impedance cardiographic waveform. In addition, an index can easily be calculated from the tracings which may be useful in identifying patients with mitral regurgitation.

The effect of atrial rhythm on the thoracic impedance cardiogram

We have observed that the thoracic impedance waveform is altered when there is a change in atrial rhythm. In order to investigate this, we selected for review impedance cardiograms of patients with various atrial rhythms. The study showed that the thoracic impedance waveform displays characteristic deflections that are specifically associated with different atrial rhythms and are analogous to those seen on the electrocardiogram. The finding that the waveform was sensitive even to the small atrial movements discernible during the rhythm of coarse atrial fibrillation was consistent with the possibility that blood flow within the vena cave-right atrial and/or the pulmonary venous-left atrial systems may be important in the genesis of the cardiac thoracic impedance waveform.

The risk of diagnostic cardiovascular catheterization

This report details a prospective study of the risk of diagnostic cardiac catheterization performed in a private, community hospital. Over the first 131 months of operation of our laboratory, 745 adult patients underwent diagnostic cardiac catheterization consisting of 2,676 various catheterization procedures. Six patients experienced seven major complications; two of these complications left a permanent deficit. There were no deaths during catheterization and none later which were attributable to it. The risk to the patient of having a major complication associated with a cardiac catheterization in our series was 0.8 per cent. The risk to the patient of having a major complication when a catheterization procedure was performed was 0.3 per cent. The risk of having a complication resulting in a permanent sequela was 0.07 per cent. We conclude that diagnostic cardiac catheterization can be accomplished with little risk to the patient, either of death or of other major complication.

Case report: factors involved in the production of the presystolic murmur in a patient with mitral stenosis and atrial trigeminy. Correlation of echocardiographic, phonocardiographic, and hemodynamic data

The study of a patient with mitral stenosis and periods of atrial trigeminal rhythm afforded an opportunity to test some factors important in the production of the presystolic murmur. The echocardiogram and phonocardiogram were correlated with hemodynamic data obtained both with the patient at rest and with right atrial and ventricular pacing. The results showed that atrial contraction was a major determinant in the production of the presystolic murmur and seemed to exert an even greater influence than did either the end-diastolic pressure gradient across the mitral valve or the duration of the preceding RR interval. Corollaries from this study may have practical application for the clinician in his bedside physical examination. The data suggested that the production of the presystolic murmur in our patient might have been related to geometrical shifts of intracardiac anatomical structures resulting from changes in the left ventricular end-diastolic distending pressure.