The wis­dom of the pul­se wave: The arte­ri­al flow resistance

Maxing out unu­sed dia­gno­stic potential

Arte­ri­al flow resis­tance is a gui­ding para­me­ter that pro­vi­des more accu­ra­te insights into indi­vi­du­al vas­cu­lar health than con­ven­tio­nal metrics.

The arte­ri­al flow resistance

The wis­dom of the pul­se wave

The arte­ri­al flow resis­tance of the major con­duit arte­ries is a rela­tively unknown para­me­ter to date and thus wide­ly unde­re­sti­ma­ted. In our opi­ni­on, howe­ver, it repres­ents the most signi­fi­cant para­me­ter of all — becau­se it acts as indi­ca­tor easy to com­pre­hend when it comes to the paten­cy of major con­duit arte­ries. This gives it far grea­ter signi­fi­can­ce than vas­cu­lar stiff­ness, which is usual­ly given pre­fe­ren­ti­al con­side­ra­ti­on. Inte­res­t­ingly, arte­ri­al flow resis­tance does not always cor­re­la­te with vas­cu­lar stiff­ness when measured.

Until now, arte­ri­al flow resis­tance has been very dif­fi­cult to mea­su­re both direct­ly and indi­rect­ly by con­ven­tio­nal means. This is whe­re Model-based Pul­se Wave Ana­ly­sis (mbPWA) makes its appearance, by far excee­ding any other dia­gno­stic approach: The under­ly­ing mea­su­re­ment prin­ci­ple is based on the indi­vi­du­al­ly deter­mi­ned vas­cu­lar data of the arte­ri­al tree of any pati­ent. Dra­wing on an algo­rith­mi­cal­ly gene­ra­ted “vas­cu­lar ava­tar”, arte­ri­al flow resis­tance can now be easi­ly and repro­du­ci­b­ly be deter­mi­ned for the first time ever: Car­dio­vas­cu­lar dia­gno­stics on a com­ple­te­ly new level.

The phy­si­cal context

To illus­tra­te, let’s take a look insi­de the arte­ries: The arte­ri­al flow resis­tance is influen­ced by the mean free lumen (the ves­sel dia­me­ter) in its func­tion as con­duc­tion resis­tance. Some­ti­mes plaques form on a par­ti­cu­lar arte­ri­al seg­ment. Plaques are patchy, inflamm­a­to­ry lesi­ons (inju­ries) of the ves­sel wall.  The under­ly­ing cau­ses are varied and have not been ful­ly explo­red in detail. Howe­ver, the­re are known risk fac­tors such as hyper­ten­si­on, dia­be­tes, dys­li­pi­de­mia, nico­ti­ne, and phy­si­cal inac­ti­vi­ty, among others. The­se fac­tors can sever­ely impair endo­the­li­al func­tion, lea­ding to vaso­con­stric­tion via seve­ral suc­ces­si­ve processes.

Con­se­quent­ly, in the cour­se of all the­se ongo­ing pro­ces­ses, resis­tance increa­ses due to the now redu­ced ves­sel dia­me­ter. When the varia­ti­on of vas­cu­lar tone, i.e., the abili­ty to dila­te or con­strict ves­sels, is limi­t­ed due to atheros­cle­ro­sis and the accom­pany­ing endo­the­li­al dys­func­tion, resis­tance increa­ses signi­fi­cant­ly even at rest. To make mat­ters worse, plaque depo­si­ti­on in the ves­sels and atheros­cle­ro­sis often occur tog­e­ther. The result of this fatal com­bi­na­ti­on is that in such seve­re cases of endo­the­li­al dama­ge, resis­tance increa­ses twice as much. The good news is that this also makes it par­ti­cu­lar­ly easy to detect the­se patho­lo­gi­cal chan­ges in mea­su­re­ments. Chan­ges in the inner dia­me­ter of the arte­ries are included in the resis­tance to the fourth degree (!).

The cli­ni­cal bene­fit of arte­ri­al flow resis­tance: lea­ding through sensitivity

In some cases, the increase in arte­ri­al flow resis­tance is detec­ta­ble at the sur­pri­sin­gly young age of 20–30 years — in pati­ents with obe­si­ty, for exam­p­le. This allows for the dia­gno­sis of pro­ble­ma­tic car­dio­vas­cu­lar con­di­ti­ons befo­re they beco­me cli­ni­cal­ly rele­vant. In many cases, con­se­quen­ti­al dise­a­ses can then be pre­ven­ted by ways of ear­ly the­ra­peu­tic inter­ven­ti­ons and per­so­nal initia­ti­ve in the sen­se of regu­lar exer­cise and healt­hy die­ta­ry routines.