Effect of cough on coronary perfusion pressure: Does coughing help clear the coronary arteries of angiographic contrast medium?

Endovascular Shunting for Communicating Hydrocephalus Using a Biologically Inspired Transdural Cerebrospinal Fluid Valved eShunt® Implant

Cerebrospinal fluid (CSF) bathing the central nervous system is produced by brain and choroid plexus within the ventricles for re-absorption into the venous circulation through arachnoid granulations (AG). Communicating hydrocephalus results from disruption of the absorptive process, necessitating surgical catheter-based shunt placement to relieve excess pressure from CSF buildup. Adjustable valve designs and antibiotic impregnation have minimally impacted persistent failure rates and postoperative complications. To confront this challenge, we have developed an innovative endovascular shunt implant biologically inspired from AG function to restore the natural dynamics of CSF drainage while concurrently addressing the predominant factors contributing to conventional shunt malfunction.

First-in-human endovascular treatment of hydrocephalus with a miniature biomimetic transdural shunt

Surgical ventriculoperitoneal shunting remains standard treatment for communicating hydrocephalus, despite persistently elevated infection and revision rates. A novel minimally invasive endovascular cerebrospinal fluid (CSF) shunt was developed to mimic the function of the arachnoid granulation which passively filters CSF from the central nervous system back into the intracranial venous sinus network. The endovascular shunt is deployed via a femoral transvenous approach across the dura mater into the cerebellopontine angle cistern. An octogenarian with intractable hydrocephalus following subarachnoid hemorrhage underwent successful endovascular shunting, resulting in swift intracranial pressure reduction from 38 to <20 cmH₂O (<90 min) and resolution of ventriculomegaly. This first successful development of a percutaneous transluminal venous access to the central nervous system offers a new pathway for non-invasive treatment of hydrocephalus and the potential for intervention against neurological disorders.

Cough-Induced Takotsubo (Stress) Cardiomyopathy

•

This case demonstrates cough as an extremely rare but notable cause of TC.

•

Plausible mechanisms include catecholamine surge, impaired cardiac microvascular and metabolic function, and extreme haemodynamic stress during cough.

•

Cough should be considered as a potential aetiology in differential diagnosis of TC.

•

There could be severe as well as subclinical cases of cough induced TC that goes unidentified.

Interpretation of cardiac pathophysiology from pressure waveform analysis: coronary hemodynamics. Part II: Patterns of coronary flow velocity

These specialized tracings illustrate several important patterns of coronary blood flow velocity that may occur in patients during diagnostic cardiac catheterization. Recent advances in catheter methodologies permit easy measurement of coronary blood flow during routine coronary angiography. At the current time, measurement of coronary blood flow velocity remains a research technique but is of continuing interest in clinical syndromes of atypical angina, myocardial hypertrophy and infarction, early transplant rejection, or premature (subangiographic) atherosclerosis in some patients. A later hemodynamic rounds will examine the effects of coronary blood flow velocity and various hyperemic stimuli to assess coronary vasodilatory reserve.

Effect of abruptly increased intrathoracic pressure on coronary blood flow velocity in patients

To assess the effects of abruptly increased intrathoracic pressure on coronary blood flow, arterial pressure, heart rate, and intracoronary Doppler blood flow velocity were measured continuously during cough(s) and again during the four phases of the Valsalva maneuver in 14 patients. Coughing significantly increased the systolic pressure (137 +/- 25 to 176 +/- 30 mm Hg), diastolic pressure (72 +/- 10 to 84 +/- 18 mm Hg), and arterial pulse pressure (65 +/- 27 to 92 +/- 35 mm Hg), with no change in heart rate. The mean coronary flow velocity decreased (17 +/- 10 to 14 +/- 12 cm/sec, p less than 0.03). During the Valsalva maneuver, despite marked reduction in the mean arterial pressure during phase III (96 +/- 12 to 68 +/- 14 mm Hg, p less than 0.05), the reduction of coronary blood flow velocity did not achieve statistical significance. These data demonstrate that neither type of abrupt physiologic increase in intrathoracic pressure enhances coronary blood flow. Coughing does not improve coronary perfusion pressures or flow velocity, despite marked increases in arterial diastolic pressure. The Valsalva maneuver, for the most part, does not significantly alter coronary blood flow velocity.

Limitations of cough in maintaining blood flow during asystole: assessment by two-dimensional and Doppler echocardiography

It has been previously demonstrated that patients can maintain consciousness by vigorously coughing during episodes of prolonged ventricular asystole or ventricular fibrillation. Using two-dimensional Doppler echocardiography and arterial blood pressure recordings, we evaluated the changes that occur during coughing in nine patients who were dependent on pacemakers and in whom periods of asystole could be induced. During asystole in each patient the mitral valve stayed partially open and the left ventricular area comprised 87% and 90% (apical four-chamber view, short-axis view, respectively) of the area during diastole of paced rhythm. Peak arterial pressure during coughing and asystole was 80% of peak systolic pressure of paced rhythm (P = 0.001). Left ventricular area during coughing was 110% (both apical four-chamber view and short-axis views) of the area during asystole when patients were not coughing. Both the mitral and aortic valves showed no appreciable motion during coughing. During coughing the mean flow velocity across the mitral valve was 0.06 +/- 0.03 m/sec and the flow velocity integral was 0.03 +/- 0.02 cm. Thus coughing during asystole produced minimal flow despite a rise in brachial arterial pressure.