Penile hypercoagulability during erection: a possible predisposing factor to ageing penile vascular changes

Haemostatic changes in the penile and systemic blood during erection were studied in the Chacma baboon. Dynamic hypercoagulability developed in the penile blood and fibrin was deposited on the endothelium of the penile artery and trabeculae during erection. These suggest that penile hypercoagulability predisposes to ageing penile vascular changes.     

Proposal: Trauma as the Cause of the Peyronie's Lesion

Purpose

We define the cause of the occurrence of Peyronie's disease.

Materials and Methods

Clinical evaluation of a large number of patients with Peyronie's disease, while taking into account the pathological and biochemical findings of the penis in patients who have been treated by surgery, has led to an understanding of the relationship of the anatomical structure of the penis to its rigidity during erection, and how the effect of the stress imposed upon those structures during intercourse is modified by the loss of compliance resulting from aging of the collagen composing those structures. Peyronie's disease occurs most frequently in middle-aged men, less frequently in older men and infrequently in younger men who have more elastic tissues. During erection, when full tumescence has occurred and the elastic tissues of the penis have reached the limit of their compliance, the strands of the septum give vertical rigidity to the penis. Bending the erect penis out of column stresses the attachment of the septal strands to the tunica albuginea.

Results

Plaques of Peyronie's disease are found where the strands of the septum are attached in the dorsal or ventral aspect of the penis. The pathological scar in the tunica albuginea of the corpora cavernosa in Peyronie's disease is characterized by excessive collagen accumulation, fibrin deposition and disordered elastic fibers in the plaque.

Conclusions

We suggest that Peyronie's disease results from repetitive microvascular injury, with fibrin deposition and trapping in the tissue space that is not adequately cleared during the normal remodeling and repair of the tear in the tunica. Fibroblast activation and proliferation, enhanced vessel permeability and generation of chemotactic factors for leukocytes are stimulated by fibrin deposited in the normal process of wound healing. However, in Peyronie's disease the lesion fails to resolve either due to an inability to clear the original stimulus or due to further deposition of fibrin subsequent to repeated trauma. Collagen is also trapped and pathological fibrosis ensues.     

Is there a significance of histamine in the control of the human male sexual response?

Although histamine has been suggested to be involved in the control of male sexual function, including the induction of penile erection, its role in the human corpus cavernosum penis is still poorly understood. The aim of our study was to evaluate the course of histamine plasma levels through different stages of sexual arousal in the systemic and cavernous blood of healthy male subjects. Thirty four (34) healthy men were exposed to erotic stimuli to elicit penile erection. Blood was aspirated from the corpus cavernosum and a cubital vein during the penile conditions flaccidity, tumescence, rigidity and detumescence. Blood was also collected in the post-ejaculatory period. Plasma levels of histamine (ng ml(-1)) were determined by means of a radioimmunoassay. Histamine slightly decreased in the cavernous blood when the penis became tumescent. During rigidity, histamine decreased further but remained unaltered in the phase of detumescence and after ejaculation. In the systemic circulation, no alterations were observed with the initiation or termination of penile erection, whereas a significant drop was registered following ejaculation. Results are not in favour of the hypothesis of an excitatory role of histamine in the control of penile erection. Nevertheless, the amine might mediate biological events during the post-ejaculatory period.     

Prostacyclin-to-thromboxane A2 ratio in arteriogenic impotence

It has been suggested that penile hypercoagulability predisposes to aging penile vascular changes and impotence, and that elevated thromboxane A2 during erection may contribute to hypercoagulability and atherosclerosis. Since the ratio of the prostacyclin concentration to the thromboxane A2 concentration is constantly maintained in normal hemostatic responses, an imbalance between thromboxane A2 and prostacyclin may be a factor to initiate vascular diseases and decrease blood flow. We assess the usefulness of the prostacyclin-to-thromboxane A2 ratio in penile blood during erection for diagnosis of arteriogenic impotence. The ratio in the arteriogenic impotence group was significantly lower (p less than 0.01) than in the psychogenic and venogenic impotence groups. Therefore, the prostacyclin-to-thromboxane A2 ratio seems to be useful to diagnose arteriogenic impotence.     

Effect of single dose aspirin on the development of penile hypercoagulability during erection

The effect of aspirin on the development of hypercoagulability in the penile blood during erection was studied in five Chacma baboons. Aspirin prevented the generation of hypercoagulability and may be of importance in delaying the development of penile atherosclerosis and ageing impotence.     

Erectile mechanism studied using penile vascular casts in the dog

The possible mechanism of penile erection was discussed based on the findings obtained by the scanning electron microscope observations of the penile vascular casts in the dog. Polsters protruding into the lumen of the distal helicine arteries regulate blood flow into the cavernous spaces. The drainage veins from the corpus cavernosum penis arose on the dorsal surface and crept on the corpus until changing direction perpendicularly. This suggested that these veins were efficiently compressed between the tunica albuginea and the corpus cavernosum penis during erection. For a high pressure to be maintained in the cavernous spaces during erection, a closed system separated from the systemic circulation must be required.     

Prostacyclin in cardiopulmonary bypass operations

The effects of prostacyclin (PGI2) on postoperative blood loss and on the deposits which are known to form on filters in the bypass circuit were studied in patients undergoing operations with cardioopulmonary bypass. In this double-blind, randomized study, PGI2 or a placebo solution was administered to 56 patients undergoing elective cardiac operations. At the end of cardipulmonary bypass, the arterial line filter was removed from the circuit and blood losses were accurately recorded. There was no statistically significant difference in either the amount or the pattern of postbypass bleeding between the PGI2 and the control patients. However, the changes in weight of the arterial line filters and their electron microscopic appearances suggest that PGI2 can reduce the deposition of platelets and fibrin on the filter mesh, and in this role it may be of value in reducing visceral injury during cardiac operations.     

Effect of platelet inhibitors on platelet and fibrin deposition following transluminal angioplasty of the atherosclerotic rabbit aorta

Experimental atherosclerosis was induced in a rabbit model by intimal damage of the infrarenal aorta followed by two months cholesterol feeding. The influence of four different antiplatelet drug regimens on acute platelet and fibrin deposition after transluminal angioplasty of the atherosclerotic abdominal aorta was then evaluated. The study group consisted of 32 New Zealand rabbits: 7 controls, 7 treated with prostacyclin (10 mg/kg/min i.v.), 5 treated with low-dose acetylsalicylic acid (2 mg/kg i.v.), 7 treated with acetyl-salicylic acid (5 mg/kg i.v.) and dipyridamole (2 mg/kg i.v.), and 6 treated with low molecular dextran (5 ml/kg). By 2 hours after angioplasty, there was a significant increase of the deposition of platelets (P less than 0.001) as well as fibrin (P less than 0.01) when comparing dilated to non-dilated segments in the control animals. There was no significant difference in the amount of platelets and fibrin deposition among the control and drug treated groups. Thus, in this animal model there appears to be no immediate benefit in using antiplatelet drugs during transluminal angioplasty. Although, this study did not address the potential long-term effects of antiplatelet drug therapy, future evaluation of the clinical benefits of these drugs in conjunction with transluminal angioplasty seems warranted.     

去氧肾上腺素治疗TURP术中阴茎勃起 (附14例报告)

目的 总结阴茎海绵体内注射去氧肾上腺素治疗阴茎勃起的临床体会，探讨其安全性及临床效果。方法 阴茎海绵体内注射去氧肾上腺素，总结起效时间、剂量、并发症的发生情况。结果所有14例患者，在2-5min内勃起消失，手术继续进行。注射前后平均动脉压及心率变化无显著差异（P〉0．05）。无并发症。结论 阴茎海绵体内注射去氧肾上腺素是治疗TURP术中阴茎勃起的安全、有效的方法。     

Predicting penile size during erection.

The aim of this prospective study was to identify clinical and engineering parameters of the flaccid penis for prediction of penile size during erection. Dorsal and ventral penile lengths, as well as base and tip circumferences were measured in flaccid states, gently stretched states and at full erection resulting from intracavernosal injection of prostaglandin E1 in 55 patients. The forces required to stretch the penis were measured by a specially designed gauge and regression relationships of the measured dimensions were calculated. An engineering model was developed to analyze differences between results obtained during stretching and erection, as well as to approximate the optimal force values which should be applied during the stretching part of the clinical evaluation of penile size. The ratio between the flaccid to stretched penile lengths was shown to be the best predictor for the ventral elongation from flaccid to erect penile lengths. The engineering analysis predicted that a minimal tension force of approximately 450 g during stretching of the penis is required to reach the potential erection length. The stretching forces exerted by the urologist in the clinical setting were experimentally shown to be significantly (P<0.01) less than this value. The values of the relative and absolute elongations of the stretched penis at its ventral aspect provide reliable estimations of its potential maximal elongation during erection. The model designed for this study may obviate the use of intracavernosal injections for estimating penile length during erection.     

Surgical/tourniquet pain accelerates blood coagulability but not fibrinolysis

Tissue damage during surgery induces coagulation factors and activates platelets. Surgical pain may provoke release of catecholamines, leading to hypercoagulability. We have investigated the effect of surgical pain on blood coagulability and fibrinolysis in orthopaedic operations using tourniquets in 22 patients undergoing total knee replacement. Patients were allocated to one of two groups to receive extradural anaesthesia (EA; n = 11) or general anaesthesia (GA; n = 11). The EA group received lumbar extradural block with lidocaine. The GA group received only general anaesthesia, maintained with 1.5-2.5% sevoflurane and 66% nitrous oxide in oxygen. Using a thrombelastogram technique, blood coagulability and fibrinolysis were measured. Mean maximum amplitude (MA), which reflects coagulability, increased after tourniquet inflation (11%) in group GA whereas MA in group EA did not change. After tourniquet deflation, MA values in both GA and EA groups increased significantly (10% and 20%, respectively) (P < 0.05), and there was also a significant difference in MA between groups (P < 0.05). The fibrinolytic rate did not change in either group during tourniquet inflation, but increased significantly (160%) after tourniquet deflation. There was no significant difference in fibrinolytic rate between the groups. We conclude that the hypercoagulability seen in group GA could have been caused by surgical or tourniquet pain, or both, and that extradural anaesthesia is a useful technique to prevent hypercoagulability.      

Questionnaire on sexual quality of life in aging couples

A questionnaire study was conducted on sexual life such as intercourse frequency, libido and erectile function and degree of satisfaction of sexual life in aging couples. Half of them had sexual intercourse and satisfaction of life. According to multivariate analysis using stiffness of penis at erection, erection maintained, and difficulty of maintenance of erection state, there was a significant relationship between satisfaction of sexual life and frequency of erection maintained or difficulty of maintenance of erection state, and also between confidence on erection and difficulty of maintenance of erection state. These values became lower because of aging. We concluded that sexual communication was needed in the life of aging couples, and an urologist should have a role in consulting on aging life.     

Artificial erection by perfusion of penile arteries

The dorsal and cavernous arteries of the penis in 14 cadavers and 4 surgical specimens were studied, and the role of these vessels in producing erection was evaluated. For the first time, erection was produced in a cadaver by the perfusion of the cavernous artery. Perfusing the dorsal artery resulted in distention but not erection, and the dorsal artery showed extensive anastomoses between all six arteries of the penis. The cavernous artery appears to be very important for erection, with the dorsal artery playing a relatively smaller role. Surgically, however, both vessels may lend themselves to vascular shunts in the treatment of vasculogenic impotence.     

A new technique for augmentation phalloplasty: albugineal surgery with bilateral saphenous grafts--three years of experience

OBJECTIVES: Penile augmentation surgery is a highly controversial issue due to the low level of standardisation of surgical techniques. The aim of the study is to illustrate a new technique to solve the problem of enlarging the penis by means of additive surgery on the albuginea of the corpora cavernosa, guaranteeing a real increase in size of the erect penis. METHODS: Between 1995 and 1997, 39 patients who requested an increase in the diameter of their penises underwent augmentation phalloplasty with bilateral saphena grafts. The patients considered eligible for surgery were patients with either hypoplasia of the penis or functional penile dysmorphophobia. All the patients included in our study presented normal erection at screening. The average penis diameter in a flaccid state and during erection was found to be 2.1cm (1.6-2.7 cm) and 2.9 cm (2.2-3.7 cm), respectively.Before surgery the patients were informed of the experimental nature of the surgical procedure. The increase in volume of the corpora cavernosa was achieved by applying saphena grafts to longitudinal openings made bilaterally in the albuginea along the whole length of the penis. RESULTS: No major complications and specifically no losses of sensitivity of the penis or erection deficiencies occurred during the post-operative follow-up period. All the patients resumed their sexual activity in 4 months. A measurement of the penile dimensions was carried out 9 months after surgery. No clinical meaningful increases in the diameter of the flaccid penis were documented. The average penis diameter during erection was found to be 4.2 cm (3.4-4.9) with post-surgery increases in diameter varying from 1.1 to 2.1cm (p<0.01). CONCLUSIONS: The penile enlargement phalloplasty technique with albuginea surgery suggested by the authors definitely is indicated for increasing the volume of the corpora cavernosa during erection. Albuginea surgery with saphena grafts has been found to be free from aesthetic and functional complications with excellent patient satisfaction.     

Platelet accumulation and fibrin deposition following peripheral laser angioplasty in rabbits

The platelet response and fibrin deposition following the delivery of an argon-ion laser beam to the rabbit ear artery has been evaluated kinetically using a minimally invasive technique utilizing⁵¹Cr-labelled platelets and¹²⁵I-labelled human fibrinogen. After laser irradiation there was an immediate increase in platelet-associated radioactivity which was followed by a series of transient increases and decreases suggesting that micro-embolization was occurring. When fibrin deposition was studied, there was a lag time of six minutes before rapid deposition of fibrin. However, once the increase in radioactivity was established the series of transient increases and decreases previously observed with⁵¹Cr-labelled platelets was not observed using¹²⁵I-labelled human fibrinogen. Histological examination of the arteries confirmed platelet accumulation and fibrin deposition. Our findings confirm that platelet accumulation with probable microembolization and fibrin deposition occurs following laser angioplasty.     

Inferior vena cava replacement: the role of antiplatelet therapy

To evaluate the effect of ibuprofen on early thrombus formation following inferior vena cava (IVC) replacement, a 4-cm segment of IVC was replaced with a 5-cm (10-mm-i.d.) segment of reinforced polytetrafluoroethylene (PTFE) graft in 12 dogs. Autologous platelets and canine fibrinogen were labeled with 111In and 125I, respectively, and injected into each animal 24 hr prior to vena cava replacement. Six dogs served as controls and six were treated with 12.5 mg/kg ibuprofen intravenously 1 hr preoperatively. All dogs were heparinized with 100 U/kg intravenous heparin prior to crossclamping the IVC: heparin was not reversed at the end of the procedure. Three hours after normal circulation was restored, the grafts were removed and counts of radioactivity made. All grafts were patent. The mean platelet count for the control group was 12.8 X 10(6)/mm2, while in the grafts from the treated group it was 0.960 X 10(6)/mm2. The decreased platelet deposition was significant in all graft segments (P less than 0.01). Fibrin deposition was reduced from 3.38 micrograms/mm2 to 0.25 micrograms/mm2 (P less than 0.01) by ibuprofen. Although fibrin and red blood cells are the major constituents of venous thrombi, platelet aggregation appears to play an important role if prosthetic material is implanted into the venous system. Ibuprofen not only reduced platelet deposition by 13.5-fold, but also reduced fibrin deposition by 13.5-fold. The ratio of platelets to fibrin in control and treated animals was similar (3.84 and 3.79, respectively). These data suggest that antiplatelet medication combined with heparin therapy might decrease early thrombus formation in venous prostheses.     

硝普钠阴茎海绵体内注射治疗阳萎的临床研究

本研究选择４２例阳萎患者，采用硝普钠进行阴茎海绵体注射（ＩＣＩ），并选择罂粟碱／酚妥拉明进行对照，结果表明，硝普钠ＩＣＩ后：（１）阴茎外形性状（长度、周径等）明显改变。（２）Ｖｉｒａｇ硬度计点表明硝普钠与罂粟碱／酚妥拉明效果之间无明显差别。（３）所有测试患者无一例出现低血压或局部不适等副反应，与罂粟碱／酚妥拉明相比各有优劣，但总体差异不大，这充分表明，硝普钠作为一种ＮＯ供体可导致阴茎平滑肌松弛，血窦充盈阴茎勃起，其副反应较小，有其临床应用之价值。     

Intraoperative pharmacological erection as an aid to pediatric hypospadias repair

PURPOSE: The intraoperative evaluation of erection is a major advance in hypospadias surgery. We determined the advantages of erections induced pharmacologically over those induced by intracorporeal saline injection for evaluating chordee during hypospadias surgery. MATERIALS AND METHODS: During the repair of hypospadias or chordee without hypospadias 56 boys 6 months to 13 years old underwent pharmacological erection induced by 14 microg. alprostadil administered intracavernously. Phenylephrine (40 microg. ) was given for detumescence. We monitored the adequacy of erection and detumescence, changes in blood pressure and pulse, and in 3 cases intracorporeal pressure. Intraoperative artificial erection was also induced in 30 patients. RESULTS: Erection occurred within 1 minute of injection. It was judged to be excellent in 47 cases and adequate in 6, while it failed in 3 probably due to injection outside of the corpora. Erection involved the whole penis, in contrast to artificial erection when tourniquet placement altered the erection and left the penile base flaccid. The degree of chordee remained stable during evaluation compared to artificial erection when curvature varied with the force of the saline injection. Erection persisted during chordee repair as long as the corpora were not opened. Detumescence occurred within seconds in all cases in which phenylephrine was given. There were no cases of priapism, and systemic blood pressure and pulse did not change. Intracorporeal pressure during pharmacological erection was 47 to 70 mm. Hg, whereas during artificial erection pressure was 50 to 250 mm. Hg depending on how much saline was injected and how rapidly fluid drained through the tourniquet. Chordee was induced by over injection. CONCLUSIONS: Pharmacological erection in hypospadias repair is effective and reliable with no significant complications. It is especially valuable in severe hypospadias and in patients with a large suprapubic fat pad. Artificial erection with saline injection should be performed with only moderate force since over filling is unphysiological and may falsely induce chordee.     

Development of a mathematical model for the prediction of the area of venous leak

Erectile dysfunction (ED) is an increasingly prevalent medical problem, affecting up to 50% of men aged between 40 and 70-y-old. Many cases are vasculogenic and some of these stem from the inability of the penis to store blood during erection due to leak into the venous system, termed corporo-venocclusive dysfunction (CVOD). The area of leakage during erection could be the most direct measure of erectile function but has not been investigated before. We have developed a simple mathematical model to determine the area of leak during erection and have tested it on data from both normal men (n=3) and men with venogenic impotence (n=16) undergoing dynamic infusion cavernosometry (DIC). The area of leak in the impotent group is significantly greater than in normal men at intracorporal pressures above 30 mmHg and reaches a plateau between 60 and 90 mmHg. Based on this study, we suggest that it may be necessary only to perform DIC at intracorporal pressures between 60 and 90 mmHg.     

The hemostatic mechanism after open-heart surgery. II. Frequency of abnormal platelet functions during and after extracorporeal circulation.

In a prospective study of 13 patients undergoing open-heart surgery with extracorporeal circulation, marked qualitative platelet function defects were observed in addition to the usually occurring drop of the thrombocyte count. At the end of bypass, the following test results were significantly abnormal: concentration of fibrinogen and of circulating fibrin degradation products, platelet count, platelet adhesiveness to glass beads, and platelet aggregation induced by low and high doses of ADP. One to 2 hours after neutralization of heparin with protamine sulfate all abnormal test results improved, but the template bleeding time was markedly prolonged in 10 patients. There was no correlation between length of bypass and platelet fall and between concentration of circulating fibrin degradation products and extent of platelet dysfunction. An apparent correlation was found between the length of the postoperative bleeding time and the number of units of blood transfued during surgery. The results of this study suggest that dilution of the patient's own platelets by nonviable platelets contained in 3-day-old transfused ACD blood and the production of a refractory state of the patient's circulating platelets to ADP induced aggregation played a significant role in the development of platelet function abnormalities during extracorporeal circulation.